Added one more slider for main volume

this closes #78

Bumped version 2.0.12

	modified:   AndroidManifest.xml
	modified:   res/layout/seekbar_dialog.xml
	modified:   res/values-de/strings.xml
	modified:   res/values-ru/strings.xml
	modified:   res/values/strings.xml
	modified:   src/com/better/alarm/model/interfaces/Intents.java
	modified:   src/com/better/alarm/presenter/background/KlaxonService.java
	modified:   src/com/better/alarm/view/VolumePreference.java