Updated DAAttributedStringUtils to 0.2, DAScratchPad to 0.4

DAAttributedStringUtils:
- Some code cleanup.
- Fixed problem with blurry text.
DAScratchPad:
- Fixes to handle sketch transparency
- Changed so setSketch: method will respect the UIImage instance's EXIF orientation data
- Changed so setSketch: method will respect the DAScratchPad object's contentMode property
- Plug memory leak in airbrush code