fix an issue with subclassing enamldef nodes
wip commit of template instantiation compiling

still need to build the engines for the nodes.
update compiler helpers
get rid of extended storage expr
remove the body of a template insantiation

The mapping semantics that were being tossed around for the body of a
template instantiation proved difficult and costly to implement. We are
likely better off without that feature.
update the template inst node
add plural correctness
minor code cleanup
remove unneeded local