Support direct import of contracts compiled with Truffle

[eepstein]

Better support for a hybrid dev env in which Truffle is used for the Solidity code including testing and deployment.

This would allow, for example, access to the deployed addresses without manual intervention.

It would also mean that the .abi and .bin inputs would be precisely those generated and used by Truffle.

As a side-effect, keeping track of addresses would allow support for looking up contract addresses on the generated instance - though integration with web3j's deploy mechanism means those values would not survive restart but would revert to the values in the generated code.

[eepstein]

I'm implemented this in a fork, along with tests.
My build is failing in :codegen:checkstyleMain
I've got the google style xml installed and ran a full reformat for the changed and new files.
bubkis.
Is there a formal .xml file for us?
...
Found the plugin: https://plugins.jetbrains.com/plugin/1065-checkstyle-idea (at least I think that's the one). Ironic thing is, the tools claims to implement the google style rules, but it doesn't actually adhere to them .
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[ant:checkstyle] [ERROR] /Users/ezra/Developer/web3j/codegen/src/test/java/org/web3j/codegen/ContractJsonParseTest.java:5: 'org.junit.Before' should be separated from previous import group by one line. [CustomImportOrder]
Wow. So Much Love.

[eepstein]

Hmm. Seems there's a requirement that AbiDefinition's equal and hashCode methods include all the ivars. But, given that Solidity functions have flags that don't factor into the uniqueness requirements of the function (e.g., you can add "pure" to a function but that doesn't change the function's uniqueness, which is determined solely by name + argument types, except for constructors where the uniqueness is by name). so, enforcing this in Java seems not to line up with the thing being modeled.

[conor10]

Implemented in #228.