Minor tweak to 0.2.0 changelog (trailing decimals).

Realized they don't need to be considered a breaking change since re-*adding*
them is a new feature -- won't break existing JSON5 files.
Readme overhaul, and add link to Google Group.
Initial work on JSON5.stringify

basic support all available
tests included
space argument partially implemented, but not tested, so currently disabled (throws exception on use)
replacer argument is not implemented (throws exception on use)
more work on stringify method

* added tests for spaces argument
* testing many more corner cases
* fixed lots of problems
Documentation and changelog
isNaN should be on Number, not Object.
Update README.md

Added a credit for the stringify method implementation.
polyfill isNaN
ensure compatibility with Node v0.6
Release 0.3.0

Update changelog