UI refactoring with a Bottom App Bar.

Only one button to play/stop.
Stop Activity to edit track just recorded, resuming or finishing.
Logo color to FF6D00.
Fixes #1078 #437 #575 #1094.

src/main/java/de/dennisguse/opentracks/settings/MainSettingsFragment.java

@@ -68,12 +68,6 @@ public class MainSettingsFragment extends PreferenceFragmentCompat {
         });
     }
 
-    @Override
-    public void onStart() {
-        super.onStart();
-        ((SettingsActivity) getActivity()).getSupportActionBar().setTitle(R.string.menu_settings);
-    }
-
     @Override
     public void onResume() {
         super.onResume();