Sets Volume to 100% on app launch
Added preference to enable max volume on start (opt-in)
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner.git into issue_375

Conflicts:
	Android/res/values/preferences_keys.xml
Merge pull request #838 from squilter/issue_375

Implemented optional max volume on start (Issue 375)