added gradle adb tasks for apk installs and test runs
move tasks to subfolder; rename some tasks
fix possible runtime exception
Merge pull request #1039 from Catrobat/catchPossibleRuntimeException

catch possible runtime exception
Merge pull request #1035 from Catrobat/adbTasks

added gradle adb tasks for apk installs and test runs
fix fatal exception
Merge pull request #1040 from Catrobat/fixFatalException

fix fatal exception
ToastManager for Toasts