update comments

contracts/extensions/contracts/OrderMatcher/MixinAssets.sol

@@ -20,8 +20,8 @@ pragma solidity 0.4.24;
 
 import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
 import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "../../tokens/ERC20Token/IERC20Token.sol";
-import "../../tokens/ERC721Token/IERC721Token.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
+import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
 import "./mixins/MAssets.sol";
 import "./libs/LibConstants.sol";
 
@@ -98,6 +98,7 @@ contract MixinAssets is
     )
         internal
     {
+        // 4 byte id + 12 0 bytes before ABI encoded token address.
         address token = assetData.readAddress(16);
 
         // Transfer tokens.
@@ -149,7 +150,9 @@ contract MixinAssets is
             "INVALID_AMOUNT"
         );
         // Decode asset data.
+        // 4 byte id + 12 0 bytes before ABI encoded token address.
         address token = assetData.readAddress(16);
+        // 4 byte id + 32 byte ABI encoded token address before token id.
         uint256 tokenId = assetData.readUint256(36);
 
         // Perform transfer.

contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol

@@ -230,7 +230,7 @@ contract MixinMatchOrders is
                     // | 932                       | a       | rightMakerAssetData Contents                |
                     // | 932 + a                   | 32      | rightTakerAssetData Length                  |
                     // | 964                       | b       | rightTakerAssetData Contents                |
-                    // | 964 + b                   | 32      | rightSigature Length (always 0)             |
+                    // | 964 + b                   | 32      | rightSignature Length (always 0)            |
 
                     // We assume that `leftOrder.makerAssetData == rightOrder.takerAssetData` and `leftOrder.takerAssetData == rightOrder.makerAssetData`
                     // `EXCHANGE.matchOrders` already makes this assumption, so it is likely
@@ -280,6 +280,7 @@ contract MixinMatchOrders is
                     )
                     mstore(rightSignatureStart, 0)
 
+                    // function selector (4 bytes) + 3 params (3 * 32 bytes) must be stored before `rightOrderStart`
                     let cdStart := sub(rightOrderStart, 100)
 
                     // `fillOrder` selector = 0xb4be83d5
@@ -288,7 +289,7 @@ contract MixinMatchOrders is
                     // Write offset to `rightOrder`
                     mstore(add(cdStart, 4), 96)
 
-                    // Write `takerAssetFillAmount`
+                    // Write `takerAssetFillAmount`, which will be the `leftMakerAssetSpreadAmount` received from the `matchOrders` call
                     mstore(add(cdStart, 36), mload(256))
 
                     // Write offset to `rightSignature`

contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol

@@ -19,7 +19,7 @@
 pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
-import "../../../protocol/Exchange/libs/LibOrder.sol";
+import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
 
 
 contract IMatchOrders {

contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol

@@ -18,7 +18,7 @@
 
 pragma solidity 0.4.24;
 
-import "../../../utils/Ownable/IOwnable.sol";
+import "@0x/contract-utils/contracts/utils/Ownable/IOwnable.sol";
 import "./IMatchOrders.sol";
 import "./IAssets.sol";
 

contracts/extensions/contracts/OrderMatcher/libs/LibConstants.sol

@@ -18,7 +18,7 @@
 
 pragma solidity 0.4.24;
 
-import "../../../protocol/Exchange/interfaces/IExchange.sol";
+import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
 
 
 contract LibConstants {