Adding screensharing sample
Adding screensharing layout
Refactoring screencapture
Fixing screensharing menu name
Clearing unused code
Fixing unused imports
Removing token and sessionId
Fixing subscriber view
Adding subscriberToSelf to true
Adding reason parameter in droppedStream callback
Removing reason from streamDropped callback
Merge pull request #41 from marinaserranomontes/sample_screensharing

Sample screensharing
Minor docs edits and info on using Android Studio.
Adding some missing docs.
Adding docs for the Emulator Hello World sample code.
More emulator docs
Docs for the screen-sharing sample code.
Removing redundant information and adding a link to the reference docs.
Minor corrections.
Info on setPublisherVideoType() and the Genymotion Android emulator.