Add tag and namespace metamethods to metaclass of taglib in initialization
- reduces missingMethod / missingProperty calls since metamethods are available upfront
- remove extra direction to call metamethod of a tag. call GroovyPage.captureTagOutput directly from all metamethods.
simplify TemplateNamespacedTagDispatcher
- call render directly without calling metamethod in taglib that contains render
- pass first non-map argument as body since that's expected behaviour