SlimOTA initial push

SlimOTA is a basic OTA app for Slimroms builded roms.

Features for initial push:
- update interval selectable
- notification on notification drawer if update is available
- several visual hints in SlimOTA app what to do and about status
- manual update check
- read changelog, faq, news.
- download rom, gapps, addons
- on app start notification if new update is available
- several hints to read changelog first
- show ProgressDialog when checking for updates

of course next versions will get more and more features....
big thanks for this work to fronti90, mnazim and tchaari

crazy guys

cheers

Change-Id: Ieee1d74360f2c44893d420f31383cb029d39416c