* move datachannel to libraries and follow new datachannel_module convention
* move datachannel to libraries and follow new datachannel_module convention
* converted from type() factory to proper ctypes.Structure subclasses
* change class to method
* bring back rtcSetLocalDescription
* rename rtc_bindings.py to datachannel.py
* rename rtc_library to datachannel_library and rearrange methods
* cleanup