v0.2 branch

This is me hacking away at a new version of dirty. The main concept stays, but things will be simpler, faster, compatible with node 0.1.30+ and less buggy : ).

Todo

• flush(cb) does not really behave properly
• dirty.close()
• dirty.forEach() or dirty.filter()
• More testing / tinkering
• Final Benchmarks
• Update docs