Scale Pixmap, Performancemodifications

Add scale-strategy 50% and 10% scale levels
Set PhysicWolrd.RATIO from 40 to 10
Set PhysicWolrd.VELOCITY_ITERATIONS from 8 to 3
Merge pull request #1084 from Catrobat/CAT_1105_Revise_Shapebuilder

Scale Pixmap, Performancemodifications