update for iOS 7 and Pixate 2.0
Merge branch 'development' of github.com:Pixate/Playground into development

# By Kevin Lindsey
# Via Kevin Lindsey
* 'development' of github.com:Pixate/Playground:
  Rename PXEngine references in build scripts and docs to Pixate
  Rename PXEngine references to Pixate
  Fix license registration call

Conflicts:
	Playground.xcodeproj/project.pbxproj
	Playground/PXAppDelegate.m
	Playground/PXPreviewThemePickerViewController.m
	Playground/PXViewController.m
	Playground/Previewers/CollectionViewController.m
	Playground/Previewers/VectorGraphicsPreview.m
	Playground/main.m