First steps towards the new background image (replacing nine box image). Refactoring and preparation.
Finished removing nine box images and replacing them with background images.  https://github.com/beautify/beautify-ios/issues/30

Note that this is only for layers that use BYControlRenderingLayer (which should be most of them). Replacement images are still hanging around - need to evaluate them.
Updated the version number for the background image change.
Merge pull request #57 from ChrisGrant/backgroundImage

Background Image