Added draft for extensions implementation
Worked on extensions
Added xtension registration function
Implemented extensions in handshakes and installed extension hooks in websocket
Code cleanup
Added some comments + input checking + template for multiplex extension
Revised extension instantiation, now 'hooks' are installed which are cleaner and more flexible
Code cleanup
Corrected typo
Bugfix & added some docs
Fixed a bug where arguments weren't passed correctly in a constructor
Improved Server contructor arguments
Fixed bug leading to tuple unpack exception