Add api for sending ping and receiving pong on WebSocket
Merge pull request #221 from zbsz/ping

Add api for sending ping and receiving pong on WebSocket
DataEmitter.charset fixes:

FilteredDataEmitter.charset now calls into underlying DataEmitter.
UrlEncodedFormBody encodes as utf8.
iml
Merge branch 'master' of https://github.com/koush/AndroidAsync

# By Koushik Dutta (2) and Zbigniew Szymański (1)
# Via Koushik Dutta
* 'master' of https://github.com/koush/AndroidAsync:
  iml
  DataEmitter.charset fixes:
  Add api for sending ping and receiving pong on WebSocket