old ICacheRefresher but now we can plugin 2 new providers - one for resolving a list of servers and the other to notify the servers of changes.
By default we have the configuration based providers which uses the umbracoSettings.
Converts UmbracoContextService and UmbracoMediaService for UmbracoExamine to use the new data api's
to extract latest data. Currently had to hack a bit with a new class called LegacyLibrary because at the moment
we'll have a circular dependency with Umbraco.Web which needs to be fixed. Moves all Examine event management to
Umbraco.Web (again mainly because of circular dependencies, but makes sense to have it there). Fixes the ExamineEvents
to implement IApplicationEventHandler instead of IApplicationStartupHandler to ensure that all resolvers have been
initialized before attempting to initialize examine indexes. Updates Examine ILogService to use the LogHelper.
Adds some new ContentExtensions for IMedia since currently Examine needs xml structures, but have kept it internal.
