- fix for external mice suggested by user jkyungit on github.
- remapped "Back" to right-click, added an on-screen Esc button instead.
- Workarounds for async access to Bitmap causing for black screen (Android 4+)
  and crashes (Android 4.3) for bVNC and aRDP.
- tweak to sensitivity
- forgot to add the esc key bitmaps to the repo
Merge branch 'external-mice-fixes'