Add feature page

[soc]

sbt-android has so many amazing features, I think it would be great if we had a dedicated page demonstrating them!

I'm thinking of

• SDK management
• Typed resources and friends
• ProGuard caching
• Protify

Anything else we should mention?

[pfn]

Indeed, it would also be nice to showcase the full list of device management commands:

• pidcat, pidcat-grep
• logcat, logcat-grep
• adb-shell, adb-reboot, adb-screenon, adb-runas, adb-kill, adb-wifi
• adb-ls, adb-cat, adb-rm, adb-push, adb-pull (all with full tab completion for remote and local files)
• devices