Lazy parse layer images
Clean up debug output for LazyExecute
Some lazy execute spec
Lazy parse all layer info blocks
README update
Change Util to a module
Fix merge
Version 1.4.4
Don't parse channel image if only retrieving width/height
Same for full image
Fixes mask parsing issues in rare cases #14
Fix some mask calculations
Dropping rubinius testing for now because it seems broken on travis
Version 1.4.5
Also create mask when #to_png called
Memorize png instance in #to_png and #to_png_with_mask
Oop! revert back the correct #build_png
Apply clipping mask before layer styles
Fix merge conflicts