app: Specify the Android Support Library version in one place
app: Specify the Android Support Library version in one place

This saves from having to update the same version number in
multiple places.

Signed-off-by: Greg Meiste <8a8f45e57c045ec63dc7e56e5eda862ea8c7cd4f@gmail.com>

meisteg/RaspberryPiTempAlarm,meisteg/RaspberryPiTempAlarm,meisteg/RaspberryPiTempAlarm