Create NSURLWebViewProtocol.h

NSURL Protocol for the UIWebView which allows users to easily define where images are located with the moustache template.
Create NSURLWebViewProtocol.m

The NSURLWebViewProtocol looks for two link prefixes in the moustache.template and will perform an NSURLRequest to request them from either the app bundle or documents location 

For example <img src="bundleimage://imagename.png" />
or <img src="documentsimage://imagename.png" />
Update PRKRenderHtmlOperation.m

Added the NSURLWebViewProtocol so that it can detect custom URLS such as bundleimage:// and documentsimage://
Update README.md

Updated README with the details on how to specify images from the app bundle or documents location.
Update README.md

Updated README so that the HTML Snippets appear correctly.
Merge pull request #12 from aaronwardle/master

Easily specify bundle or documents location for the HTML Template