Updated version.

Updated version to 3.1.1 in docs.

Merge pull request hyperledger-web3j#243 from joanesespanol/android

Android

1. Added MetaCoin smart contract wrapper to integration-tests module …

…and build script.

2. Documentation updates.

1. Bumped version.

2. Added toBigIntNoPrefix utility function.

Updated version in conf.py.

Updated version in conf.py.

1. Bumped version to 3.0.0 in preparation for release.

2. Added ABI & RLP sections to documentation, plus numerous other updates.
3. Updated ChainIds to be correct as per latest EIP-155.
4. Added TransactionUtils for generating transaction hashes.

Merge pull request hyperledger-web3j#212 from mochalovv/fix/issue_#211

Removing the duplicated calls for installing and uninstalling the filter

Fixed import ordering.