Add audio and video options example for users 

Users have requested a way to restrict audio or video input so with minimal code changes there is now an example to set options with each SimpleWebRTC instance. 

### index.html
* Line 58 to 66 have two examples for setting the audio and video options by passing in the media options object. 

### simplewebrtc.js
* Create a first option for the config object and allowing to fall back to original options if and opts.media object was not passed in. 

### simplewebrtc.build.js and latest.js
* Changes resulted from "node build.js" changes. 

*** Note: users should note they need to deal with empty containers in the id:remotes div if the video feed is restricted.