AsyncHttpClient: watch and report invalid URIs.
ByteBufferList: add support for compacting.
Watch for null values on UrlEncodedFormBody.

If a connection dies during completion, do not attempt to reconnect. Instead fail.
Merge branch 'master' of https://github.com/koush/AndroidAsync

# By Koushik Dutta
# Via Koushik Dutta
* 'master' of https://github.com/koush/AndroidAsync:
  Watch for null values on UrlEncodedFormBody.
  AsyncHttpClient: watch and report invalid URIs. ByteBufferList: add support for compacting.