*WIP, will be rebased!* CLJS-643: make the ClojureScript compiler (more) idempotent:

* moved cljs.closure/compiled-cljs cache into *compiler-env*
*WIP, will be rebased!* CLJS-643: make the ClojureScript compiler (more) idempotent:

* start documenting what can be found in compiler env maps
* use namespaced keyword for the constants-table, too
* make cljs.analyzer/constant-counter private