stomp-client refactoring for more stability and transparency

We detected some dead loops using this client in our project, so we started to remove them.
- Extracted some classes in order get better testabillity.
- Fixed travis-ci config.
- Increase code coverage.
- Removed automatic reconnect in background, this might lead to unexpected results.
- Removed sslTests (Yes, they don't depend on this stomp client, it's php only!)
- Removed stubbed tests, they didn't work at all

This pull request should address following issues:
 - https://github.com/dejanb/stomp-php/issues/30
 - https://github.com/dejanb/stomp-php/issues/27
 - It also opens some new possibilities, since it's easier to create own parser, protocols and connections now.

I know it's a bigger commit, hope you have the time to check it. Thank you!