Optimize shows_row for Nexus 7 screen.
Reduce start and end margin on search bars.
Do not show text for most action items regardless of screen size.
Add some screen size helpers to DisplaySettings.

- Added isVeryLargeScreen() and isVeryLargeAndHighResScreen(), use them
everywhere we previously checked manually for R.bool.isLargeTablet.
- Also made isVeryLargeAndHighResScreen() compatible with API level 8.
Did not crash before, because is guarded by xlarge screen detector.
Fix cut-off ratings.
Use narrow show info on w590dp to w1014dp screens.