android: removed 'play sound' button from start activity.
Merge branch 'master' into control-car
android: added 'play game' activity
android: when selecting a car, the app will switch to the 'play game' activity.
android:
 - added basic layouts: 'choose control mode' and 'standard controls'
android: set 'playerReady'.
- also, change to the chosen control mode _after_ the player was set to ready.
android: actually control the car
Merge branch 'master' into control-car
Merge pull request #6 from lumannnn/control-car

Control car