[2/2] OmniGears: fix ActiveDisplay for WifiOnly Devices

fix http://jira.omnirom.org/browse/OMNI-637
also fix for devices with unsupported Proximity sensor and Light sensor

Change-Id: I19a8c2cf1afbf7c631d27481ed84e700ba56368f
[2/2] OmniGears: more improve Active Display

1. fix http://jira.omnirom.org/browse/OMNI-651
2. fix http://jira.omnirom.org/browse/OMNI-641
3. add http://jira.omnirom.org/browse/OMNI-652
4. Add option Double tap to sleep every where
5. Add option to show and choose wallpaper behind active display
6. Allow to show numbers of notification on Handle
7. minor improvements
8. add battery circle around handle

PS8
string rework

PS9
recalc brightness to % value

Change-Id: Iceaae6eecbdd3dbce4347b2e3994272b10f3c490
[2/2] OmniGears: remove ActiveDisplay wallpaper

see also https://gerrit.omnirom.org/#/c/6087/

Change-Id: Ia8de23930a83f7f6abed5eaff492f91c7992572e
Update crom_strings.xml