Factor shared array & map functions into utils file
Remove old array cruft
Add some initial code for persistent maps
Add some initial-cut ADD code for persistent-maps
Add persistent-map copier func
Remove unused tail slot
Initialize the root node on map creation
Fix typecheck
Pass item hash instead of item
Fix arg-parsing bug
Don't rely on ELEMENT for a default val
Add PRINT-OBJECT method for persistent maps
Initialize height correctly
Fix off-by-one error when adding parent nodes
Define method after class
Avoid clobbering a root that's been set
Add deep copier for map nodes
Handle insertions in the middle of an item list
Set the default node bits based on the size of fixnum
Use partition count instead of (wrong) max-partition