Re-order methods appropriately.
Remove the rendering switch statement by having the Theme ask each
Element how to render itself, then each Element asking the Theme to
render it in the correct way.
Fix incorrect method call.
Add Environments to hold static application configuration
Add PHP mbstring extension, as  we require it for common string
operations.
Add missing render methods for existing elements.
Implement render methods for basic elements.
Implement markup element.
Make a fieldset a container for the time being, as they share a lot in
common.