CLJS-1375: cljs.js/require does not conj to *loaded*
CLJS-1375: cljs.js/require does not conj to *loaded*

Use Mike Fikes changes which highlighted some broken thigns.

require did not invoke the callback if library was already loaded. Macro namespaces
need to be renamed, otherwise unintuitively prevents loads.

mstang/clojurescript,mstang/clojurescript,mstang/clojurescript