Major updates for DataChannel and init functions

- Fixed bugs for DataChannel
- Changed init function implementation. It takes in a options (JSON) or just the appID (String)
- Changed the joinRoom function implementation to take in a options (JSON) parameter. Audio required for call or both audio and video?
- Changed the getDefaultStream function implementation to take in a options (JSON) parameter. Audio true or Video true?
- Updated documentation and format of retrieving DataTransfer states