Finish moving wallet related classes to .wallet package.

These classes are moved to .wallet:
- Wallet + WalletTest
- WalletExtension + WalletExtensionsTest
- WalletProtobufSerializer
- UnreadableWalletException

These classes are moved to .wallet.listeners:
- WalletEventListener
- WalletChangeEventListener
- WalletCoinsReceivedEventListener
- WalletCoinsSentEventListener
- WalletReorganizeEventListener
- ScriptsChangeEventListener
- AbstractWalletEventListener
- KeyChainEventListener
- AbstractKeyChainEventListener

examples/src/main/java/org/bitcoinj/examples/BackupToMnemonicSeed.java

@@ -16,9 +16,9 @@ package org.bitcoinj.examples;
 
 import org.bitcoinj.core.NetworkParameters;
 import org.bitcoinj.core.Utils;
-import org.bitcoinj.core.Wallet;
 import org.bitcoinj.params.TestNet3Params;
 import org.bitcoinj.wallet.DeterministicSeed;
+import org.bitcoinj.wallet.Wallet;
 
 /**
  * The following example shows you how to create a deterministic seed from a hierarchical deterministic wallet represented as a mnemonic code.

examples/src/main/java/org/bitcoinj/examples/DoubleSpend.java

@@ -20,6 +20,7 @@ import org.bitcoinj.kits.WalletAppKit;
 import org.bitcoinj.params.RegTestParams;
 import org.bitcoinj.utils.BriefLogFormatter;
 import org.bitcoinj.utils.Threading;
+import org.bitcoinj.wallet.Wallet;
 
 import java.io.File;
 

examples/src/main/java/org/bitcoinj/examples/DumpWallet.java

@@ -16,10 +16,10 @@
 
 package org.bitcoinj.examples;
 
-import org.bitcoinj.core.Wallet;
-
 import java.io.File;
 
+import org.bitcoinj.wallet.Wallet;
+
 /**
  * DumpWallet loads a serialized wallet and prints information about what it contains.
  */

examples/src/main/java/org/bitcoinj/examples/ExamplePaymentChannelClient.java

@@ -29,6 +29,9 @@ import org.bitcoinj.protocols.channels.StoredPaymentChannelClientStates;
 import org.bitcoinj.protocols.channels.ValueOutOfRangeException;
 import org.bitcoinj.utils.BriefLogFormatter;
 import org.bitcoinj.utils.Threading;
+import org.bitcoinj.wallet.Wallet;
+import org.bitcoinj.wallet.WalletExtension;
+
 import com.google.common.collect.ImmutableList;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;

examples/src/main/java/org/bitcoinj/examples/ExamplePaymentChannelServer.java

@@ -24,11 +24,12 @@ import org.bitcoinj.core.Coin;
 import org.bitcoinj.core.NetworkParameters;
 import org.bitcoinj.core.Sha256Hash;
 import org.bitcoinj.core.VerificationException;
-import org.bitcoinj.core.WalletExtension;
 import org.bitcoinj.kits.WalletAppKit;
 import org.bitcoinj.params.RegTestParams;
 import org.bitcoinj.protocols.channels.*;
 import org.bitcoinj.utils.BriefLogFormatter;
+import org.bitcoinj.wallet.WalletExtension;
+
 import com.google.common.collect.ImmutableList;
 
 import com.google.common.util.concurrent.ListenableFuture;

examples/src/main/java/org/bitcoinj/examples/ForwardingService.java

@@ -24,6 +24,9 @@ import org.bitcoinj.params.MainNetParams;
 import org.bitcoinj.params.RegTestParams;
 import org.bitcoinj.params.TestNet3Params;
 import org.bitcoinj.utils.BriefLogFormatter;
+import org.bitcoinj.wallet.Wallet;
+import org.bitcoinj.wallet.listeners.WalletCoinsReceivedEventListener;
+
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.MoreExecutors;
@@ -31,7 +34,6 @@ import com.google.common.util.concurrent.MoreExecutors;
 import java.io.File;
 
 import static com.google.common.base.Preconditions.checkNotNull;
-import org.bitcoinj.core.listeners.WalletCoinsReceivedEventListener;
 
 /**
  * ForwardingService demonstrates basic usage of the library. It sits on the network and when it receives coins, simply

examples/src/main/java/org/bitcoinj/examples/Kit.java

@@ -18,14 +18,16 @@ import org.bitcoinj.core.*;
 import org.bitcoinj.kits.WalletAppKit;
 import org.bitcoinj.params.TestNet3Params;
 import org.bitcoinj.script.Script;
+import org.bitcoinj.wallet.Wallet;
+import org.bitcoinj.wallet.listeners.KeyChainEventListener;
+import org.bitcoinj.wallet.listeners.ScriptsChangeEventListener;
+import org.bitcoinj.wallet.listeners.WalletCoinsReceivedEventListener;
+import org.bitcoinj.wallet.listeners.WalletCoinsSentEventListener;
 
 import java.io.File;
 import java.util.List;
-import org.bitcoinj.core.listeners.WalletCoinsReceivedEventListener;
-import org.bitcoinj.core.listeners.WalletCoinsSentEventListener;
-import org.bitcoinj.core.listeners.ScriptsChangeEventListener;
+
 import org.bitcoinj.core.listeners.TransactionConfidenceEventListener;
-import org.bitcoinj.wallet.KeyChainEventListener;
 
 /**
  * The following example shows how to use the by bitcoinj provided WalletAppKit.

examples/src/main/java/org/bitcoinj/examples/PrivateKeys.java

@@ -20,6 +20,7 @@ package org.bitcoinj.examples;
 import org.bitcoinj.core.*;
 import org.bitcoinj.params.MainNetParams;
 import org.bitcoinj.store.MemoryBlockStore;
+import org.bitcoinj.wallet.Wallet;
 
 import java.math.BigInteger;
 import java.net.InetAddress;

examples/src/main/java/org/bitcoinj/examples/RefreshWallet.java

@@ -21,9 +21,10 @@ import org.bitcoinj.core.*;
 import org.bitcoinj.params.TestNet3Params;
 import org.bitcoinj.store.BlockStore;
 import org.bitcoinj.store.MemoryBlockStore;
+import org.bitcoinj.wallet.Wallet;
+import org.bitcoinj.wallet.listeners.WalletCoinsReceivedEventListener;
 
 import java.io.File;
-import org.bitcoinj.core.listeners.WalletCoinsReceivedEventListener;
 
 /**
  * RefreshWallet loads a wallet, then processes the block chain to update the transaction pools within it.

examples/src/main/java/org/bitcoinj/examples/RestoreFromSeed.java

@@ -20,6 +20,7 @@ import org.bitcoinj.net.discovery.DnsDiscovery;
 import org.bitcoinj.params.TestNet3Params;
 import org.bitcoinj.store.SPVBlockStore;
 import org.bitcoinj.wallet.DeterministicSeed;
+import org.bitcoinj.wallet.Wallet;
 
 import java.io.File;
 

examples/src/main/java/org/bitcoinj/examples/SendRequest.java

@@ -18,9 +18,10 @@ import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import org.bitcoinj.core.*;
-import org.bitcoinj.core.Wallet.BalanceType;
 import org.bitcoinj.kits.WalletAppKit;
 import org.bitcoinj.params.TestNet3Params;
+import org.bitcoinj.wallet.Wallet;
+import org.bitcoinj.wallet.Wallet.BalanceType;
 
 import java.io.File;