added UserBrick
User Bricks category
My Bricks category with blank brick runs without errors
Less Ugly graphics
cleanup
Merge remote-tracking branch 'github/userbricks' into userbricks
WIP UserBrick
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User Bricks visible in category view with code-defined text
adding User Bricks to script works
First time that we can open UserBrickScriptActivity on a user brick
User Bricks saved in the Sprite, runtime works minus parameters.
UserBricks correctly stored in the project
Merge remote-tracking branch 'catrobat/master' into userbricks

Conflicts:
	catroid/src/org/catrobat/catroid/common/StandardProjectHandler.java
Tested basic operation after merging with master