Hide internal implementation classes in ExtensionRegistry
Don't use deprecated ExtensionRegistry constructor
Remove deprecated getExtensionContext variant
ExtensionRegistry should not cache any ManagementResourceRegistration so it won't use the wrong one if it's cloned
[WFCORE-21] Revert ExtensionRegistry changes if the operation that made them rolls back
ExtensionRemoveHandler doesn't need to set reload-required
Merge pull request #68 from bstansberry/clone-ext-reg

ExtensionRegistry clean up