Secure websockets

This allows LeapJS to work over TLS to the latest internal builds of the Leap Service.  To test (requires Leap Service 2.0.6 or greater). 

https://leapmotion.github.io/leapjs/examples/dumper.html

I've added a section to the wiki on SSL: https://github.com/leapmotion/leapjs/wiki/Protocol#ssl

CC @jo3w4rd @gittyupagain @raimo