Crash with NoClassDefFoundError caused by setSupportActionBar of compat-v7

[LiliWeiSE]

Dear developers of open-gpstracker,

I have found out that the method setSupportActionBar of android support library v7 is used in the SettingsActivity. However, this method crashed the app on Samsung devices.
The discussion can be found in the bug tracking system of Android: here.
Numbers of apps are affected by this problem. And fixes were found effective by using the proguard like in comment #308 or somebody reports that there's a valid workaround for this issue in 24.0.0-alpha1.

Thank you very much if you can fix this. Hope this information is helpful. :)