Litecoin trade-bot added!

Several cross-chain API calls moved into separate classes,
although most of the URLs remain roughly the same to provide
backwards compatibility.

API /crosschain/at/build moved into /crosschain/BitcoinACCTv1

Converted DELETE /crosschain/tradeoffer to be ACCT-agnostic.
Changes to ACCT interface, etc. to support above.

Changes applied to other crosschain API calls to make them
independent of Bitcoin/Litecoin.

Corrections to fee calculations and usage in BitcoinACCTv1.

Added new LitecoinACCTv1 trade-bot, using LitecoinACCTv1.

Some minor typo corrections, rename of secretHash to hashOfSecret.

Some more Bitcoin-specific fields deprecated, but values duplicated
from newly-named fields for now.

Lower default fee (10sats/byte) for Litecoin spending transactions.
(Not P2SH fees which are 1000sats).

Changed ApiError INSUFFICIENT_BALANCE HTTP status from 422 to 402
as 422 isn't supported by Jetty?

CrossChainTradeSummary.btcAmount deprecated, use: foreignAmount

Modified pom.xml to generated package-info.java files for classes
inside org.qortal.api.model.** subdirectories.

pom.xml

@@ -200,6 +200,10 @@
 							<pattern>org.qortal.api.model**</pattern>
 							<template>${project.build.sourceDirectory}/org/qortal/data/package-info.java</template>
 						</package>
+						<package>
+							<pattern>org.qortal.api.model.**</pattern>
+							<template>${project.build.sourceDirectory}/org/qortal/data/package-info.java</template>
+						</package>
 					</packages>
 					<outputDirectory>${project.build.directory}/generated-sources/package-info</outputDirectory>
 				</configuration>