fixed issues #910, #909 and #906

Feature_Backpack_Enabled can be set in build.gradle

changed the strings accordingly

removed checkstyle warning

added check if BuildConfig.FEATURE_BACKPACK_ENABLED is true

fixed TODO
add tasks to switch to old branches
Merge pull request #915 from Catrobat/issues910_909_906

fixes [CAT-917]
fixed issues #910, #909 and #906
Merge pull request #1029 from Catrobat/switchToOldBranches

add tasks to switch to old branches
Physic-Integration, create packages and Datatypes,

first step, not yet used
physic integration- modify, actions, new classes

add: physicactions; physicfactory modify: Sprite, Project
add bricks, layouts, res
StageListener, PreStageActivity, Factory

PhysicWorld step.....
move ExtendedActionFunctions

move remaining ExtendedActionFunctions to ActionFactory
add PhysicActionMultiStepExtension + modifications
file
add requiered png's for physic standartproject
PhysicsLook
physicObject
Fix PhysicsLook positioning bug.

Add x/y-getters for PhysicsLook.
Update pinball standard project rotation values.
Replace Sprite resources member with query.
Disable nonrelevant render settings.
rm PhysicActions, PhysicFactoryFunctions .....

remove unused PhysicActions
remove unused Functions in PhysicFactory
remove default BoundaryBox
rm physichock,TemporalAction,IfOnEdgeBounceAction

no need for hocks anymore -> physiclook
let the look know about the begin and end of a TemporalAction
Override-> createIfOnEdgeBounceAction [ActionPhysicsFactory]
collision - step
fixGlideTo and refactor BitMask for collision
Testcase-Fixes Part one