Separate qunitjs tests with and without WebRTC. Make "grunt test" to run "grunt testNoWebRTC".
Make JsSIP.URI and JsSIP.NameAddrHeader more robust.
Fix URI schema default value.
Improvements and some bug fixes in URI and NameAddrHeader classes.
Test units for URI and NameAddrHeader classes.
Fix. Add headers to the JsSIP.URI instantiation from grammar.
Improvement in UA.getCredentials() (use RURI instead of To header for getting the realm).
Added test unit parsers for Via and CSeq headers.
Extend the use of the 'options' argument

..to

- Message.accept()
- Message.reject()
- Session.cancel()
- Session.answer()
- Session.terminate()
- Session.reject()
check for HTMLVideoElement only if video is enabled
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/Grammar/dist/Grammar.js
Added Anthony Minessale to THANKS file.
JsSIP.Utils.parseURI() moved to JsSIP.URI.parse(), and URI scheme is now required.
Make JsSIP.URI.parse() to return undefined rather than null if an invalid URI is given.
Add JsSIP.Utils.createRandomToken utility to create random tokens
Fix typo
Use a random user in the UA's contact.

- Compare the received Contact headers in response to a REGISTER against such random user
Cosmetic changes.
Add Name_Addr_Header grammar rule
JsSIP.URI.toAor() now accepts 'show_port' param. When true the port is added to the resulting string (if there is port).