Revise and add to docs everywhere except mediation.

I had to import `android.view.ViewGroup' into the interstitial ad view
file to get the Javadocs to build.
Cleanup xml description

Documentation change
Revised & updated docs in mediation-related files.
Update gitignore
MS-390 Application crash on invalid API

setScaleX requires API 11
setLayoutDirection requires API 17

Changed play button rendering to use Matrix rotation
Tweaks for crash fix from Ron
Merge branch 'master' into github
MS-124 remove retrying requests from SDK
MS-124 unit tests updates, move package
MS-397 updating debug auction in app to show device info.
Merge remote-tracking branch 'origin/master'
MS-124 return null for no network or context case.
Merge branch 'ms124'
MS-385 make display protected in InterstitialAdView to hide from javadoc
MS-386 refactored mediation to create private displayable object, hide inner classes from javadoc
MS-386 update interstitials for new MediatedDisplayable
MS-386 CR-159 use private variables
MS-398 use last request as base url for debug auction
Update gitignore
MS-390 Application crash on invalid API

setScaleX requires API 11
setLayoutDirection requires API 17

Changed play button rendering to use Matrix rotation