Ensure consistent library version across different files.

https://code.google.com/p/esprima/issues/detail?id=470
Use ESLint to lint the code.

https://code.google.com/p/esprima/issues/detail?id=473
Use single-quoted string literals.

https://code.google.com/p/esprima/issues/detail?id=398
ESLint should tolerate assignment to a function.

Until this harmony branch doesn't use the tracker wrapper approach,
we still need to allow assignment to/from a function.

https://code.google.com/p/esprima/issues/detail?id=473
Fix ESLint errors: trailing comma and non-camel case ids.

https://code.google.com/p/esprima/issues/detail?id=473
Allow YieldExpression in an argument of YieldExpression

The current latest draft (Rev 21) allow YieldExpression in an argument
of YieldExpression. e.g. `yield yield v`

https://code.google.com/p/esprima/issues/detail?id=476
Present diffs for mismatched actual and expected JSON.

https://code.google.com/p/esprima/issues/detail?id=478
Expression closure in not supported anymore.

https://code.google.com/p/esprima/issues/detail?id=455
https://code.google.com/p/esprima/issues/detail?id=332
Add more unit tests for arrow functions

https://code.google.com/p/esprima/issues/detail?id=488
Merge remote-tracking branch 'upstream/harmony' into fb-harmony

Conflicts:
	esprima.js