we have to instantiate them all on startup which means that all type searching happens on startup and not lazily which
is bad for performance. I don't think its a big deal that we're not freezing these objects, MVC doesn't freeze its singletons
and nobody seems to have a problem with it, people will just know not to modify these items after startup.
Have removed ResolverBase as we cannot rely on manually setting the current singleton object since applications outside of the standard umbraco web application
might be using these singletons and would expect they already be setup. Have changed all current resolvers to manage their
own singleton instances and sealed them.
and are just adding the known resolvers on app startup and commented out the other resolver stuff for now.
Fixed up xpath statement for resolving the first document, site now renders :)
