add a sophisticated View for ImageView overlays including rotation.
add first speedometer prototype
adjust dashboard layout
Merge branch 'develop' of https://github.com/matthesrieke/enviroCar-app into develop

Conflicts:
	org.envirocar.app/res/layout/dashboard.xml
	org.envirocar.app/src/org/envirocar/app/activity/DashboardFragment.java
add custom views to fit the actual screen/root view size.
fix issues with screen density and TextView's textSize.
add CAR_HASH_CODE preference. fixes #180

the long base64 serialized strings only differ a minor bit. obviously
Android SharedPreferences did not fire a change event due to that. This
is why an additional pref was required.
merge bugfix for #180
initial fix for uploading tracks without meaasurements. fixes #183
merge fix for #183
Merge pull request #188 from matthesrieke/develop

Develop