simple-check now Clojure/ClojureScript portable via cljx, fixes gh-11
Refactor `defspec` impl to avoid repeated re-defs in ClojureScript.

The prior approach was producing undefined function references in
:advanced-optimized JavaScript, perhaps due to fn references going
stale in the _ClojureScript_ compiler...?
fix prop/for-all => for-all
initial README, project.clj tweaks for double-check fork
disable edn round-trip test on CLJS until CLJS-677 is fixed
Tweak CLJS install doc
more CLJS usage docs