Define syntax of maps literal

This is the first version and uses a very simple representation.
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.
Fix handling of comment so lone comment is returned

This has been fixed for both defun and defmacro. Note for match case
the comment is always been removed for there should follow clauses.
Improve pretty printing of maps
Add maps visual test files
Change to latest maps interface
Merge branch 'maps-dev' into develop