Bug fix in Netty impl.
Few enhancements/bug-fixes:

1) Revamped the client to not switch the executor unless connect failed or retry. Earlier it was switching for every connect & response listener invocation.
2) Carrying forward the promise initially given to the caller of HttpClient even in retries. This may have caused incompleted requests.
Merge https://github.com/benjchristensen/WSPerfLab
Handling null completion promise on client exception.
Bug fix
Bug fix
Bug fix
Fixing netty blocking install scripts
Adding event loop counts for blocking netty impl
Adding event loop counts for blocking netty impl
Hack to workaround netty's issue of failure to add listener to a connect promise when connect failed due to too many channels in OIO.
Merge pull request #17 from NiteshKant/master

Netty blocking impl fixes