Prettyprint maps as well
Add experimental map forms map, get-map, set-map and update-map

Also defined and exported a literal eval function used in the map
matching. As error fixed indentation.
Add better checking of map keys
Use the new lfe_eval:literal function to create literal binaries

Also fix stupid miss which made parsing [ ... ] impossible.
Add alternate map forms

These are (mref k m) (mset k v ... m) (mupd k v ... m)
Add map forms to compiler

Currently we support both versions of the map forms as this is
experimental.