Add get_gathering_state() returning the iceGatheringState of the
connection.
Add get_signaling_state() returning the signalingState of the
connection.
Improve JS library.
This makes it easier to spot syntax errors when editing the
class reference. The schema is referenced locally so validation
can still work offline.
Each class XML's schema conformance is also checked on GitHub Actions.
Fabio Alessandrelli
Yuri Sizov
Hugo Locurcio