SlimFileManager : Root functionalty

- Root Browsing
- Remount R/W / Delete
- Copying, Moving, Renaming (+minor tweaks)

Patchset 6: fixing RootTools' broken "mounted as" detection to fix remount issues with /system
Patchset 7: Don't reset on device rotation, minor Rename Dialog tweaks
Patchset 8: Allow paths with spaces
Patchset 9: Thumbnail creation fixes (more efficient/less memory, centercrop 52x52, fix some potential Exceptions)
Patchset 10: Killing more potential thumbnail exceptions

Change-Id: Ie035215d6e9c9de0cd247c0e7fc11a9af0144e2e