Changed PluginResolverType to PluginManager. Reinstated Resolution and ResolverBase<T> since

this gives us more control over all Resolvers and streamlines them. Created IBootManager, CoreBootManager and WebBootManager
to handle the application initialization including the creation of Resolvers. This means that if people are using the dlls outside
of the web app, they can run the boot strappers to initialize everything.

src/Umbraco.Core/Resolving/SingleObjectResolverBase.cs

@@ -6,12 +6,14 @@ namespace Umbraco.Core.Resolving
 	/// A Resolver to return and set a Single registered object.
 	/// </summary>
 	/// <typeparam name="TResolved"></typeparam>
+	/// <typeparam name="TResolver"> </typeparam>
 	/// <remarks>
 	/// Used for 'singly' registered objects. An example is like the MVC Controller Factory, only one exists application wide and it can
 	/// be get/set.
 	/// </remarks>
-	internal abstract class SingleObjectResolverBase<TResolved>
+	internal abstract class SingleObjectResolverBase<TResolver, TResolved> : ResolverBase<TResolver>
 		where TResolved : class
+		where TResolver : class
 	{
 		TResolved _resolved;
 		readonly bool _canBeNull;