Initial take on Extension Support

- TYRUS-266: Extension support
- TYRUS-283: permessage-compression extensions
- TYRUS-280: Extension parser now allows params without values

Additional tasks done (no JIRA issues):

- Refactored frame represenation (part of TYRUS-266)
  - org.glassfish.core.Frame
- Added test for ExtendedExtension (name might change)
- Added test for CompressionExtension
- Autobahn test suite is 100% green (including compression tests)

TODOs:

- validation (Frame, ExtendedExtension#*, ...)
- exception processing (thrown during ExtendedExtension# processIncoming & processOutgoing)