Merge pull request #13 from joseph-onsip/master

(Android) allow optional DTLS
Statically add local video stream
Add remote video tracks to the view statically when available
Ignore gestures on video elements
Add javascript to pull video elements off page and pass to native iOS
Put native video elements ontop of web video elements
Cleanup initial video placement code.
Move video elements as page is scrolled.
Create shared constraints to use accross multiple function calls
Only add video frames if enabled from javascript
Only capture video if you plan on using it
Cleanup video when call completes
Update readme with video instructions
Merge pull request #15 from egreenmachine/ios-video

iOS video
Fix spelling mistake: DtlsSrtpAgreement => DtlsSrtpKeyAgreement
Prevent video calls from crashing after first call
Replace excessive NSNotification center calls with delegate.
Remove dispatch_async that is causing crashing.
Merge pull request #16 from egreenmachine/ios-video-fixes

iOS video fixes
chore(readme): merge code examples, add cordova.require
fix(cordova): stop coping phonertc.js to www
feat(android): experimental video chat

Note: Implementing updateVideoPosition isn't necessary because the GL
surface is added as a child view to the WebView, so that scrolling works
automatically.