Merge pull request #3 from SimonMarquis/master

Replace CheckBoxPreference by a master Switch in the ActionBar
remove unused string
bumped version to 1.0.2
update screenshots
added option to toggle kitkat gradient on/off - fixes #4
bumped version to 1.0.3
updated before/after
Add navigation bar customization
Switch between status bar and navigation bar + disable preferences when master switch is off, or when dependency required
Use string resources for Preferences keys instead of Strings
Fix color selection + add disabled state for ColourPreference