- update older ObjMap
- simple-hash-map to avoid name collision

- switch to HashMap/EMPTY

…an use this util then

- avoid map in ObjMap for now until we get our ducks in a row

…mpossible to respect the O(1) copy contract, but too much of cljs.core relies on the protocol, we have to pretend we support it

…ed to add a case to macro expansion

…an internal detail

- testing stuff wip

- don't leak internal key rep from ObjMap

- cleanup ns form

- add missing -contains-key? method to Vector