ClojureScript support.
Change project.clj so lein-cljsbuild and codox work.
Clean up tests so they all pass on both clj and cljs.

Remove tests that depend on specific parsing of doctype in cljs.
Remove test that depended on specific parsing of whitespace in clj and cljs (wasn't that useful).
Move lower-case-keyword into hickory.utils.

Update core.clj and core.cljs with this change.
Fix a reflective call in hiccup-utils's index-of function.