signatures of IApplicationEventHandler methods to accept an UmbracoApplicationBase object instead of UmbracoApplication. This allows
us to execute all IApplicationEventHandler's outside of the web context. Added unit test to support booting the application outside of the
web context.
Created new CacheHelper which replaces the old Cache class and is accessible via the UmbracoContext.
Added new CachedPartial extension method to be able to cache the output of your partials (also by page and by member)
Added mew CacheHelperApplicationEventListener in order to automatically clear the partials cache when content is published, media or members is saved.
