adds tests to verify that implicit return of xmlnode as well as explit result from renderHtml get doctype element prepended
adds test to verify that doctype is not prependend in case where the user returns a fully parsed html document as string
*changes direct calls of context writer methods to helper methods (to keep interface uniform)
adds tests to verify that implicit return of xmlnode as well as explit result from renderHtml get doctype element prepended adds test to verify that doctype is not prependend in case where the user returns a fully parsed html document as string *changes direct calls of context writer methods to helper methods (to keep interface uniform)