Change how relative urls resolve in iOS

This is a breaking change. Currently relative urls are resolved from
the public/views directory, which means to request any assets you
always need to navigate up a level (../scripts/init.js).

This change sets the base URL for the webview to /public. Relative
paths now don't need the ../.
Add a URLProtocol that maps absolute paths to the bundle path

This change allows you to use absolute urls in your HAML files and have
them resolve correctly even though the page is requsted as a file://.
Merge branch 'ios-absolute-urls'

Conflicts:
	calatrava-ios.xcodeproj/project.pbxproj
Merge branch 'ios-relative-urls'

Conflicts:
	calatrava-ios/Shell/WebViewController.m