Various fixes and improvements.
Merge pull request #36 from dwelch91/master

Fix for sslopt and some other improvements
- prepare for 0.12.0
- abolish _SSLSocketWrapper
- fixed #32 Keepalive / ping ?
- fixed #42
- fixed #38
  - show error log if a error occurs.
- refs #38
  - print stacktrace if the logging level is debug
- fixed #42
- fixed #40
  - if timeouted, raise WebSocketTimeoutException for ws/wss.
- fixed #44