Add map and mapi
Size -> Empty (in previous commit)
Add peeks to accompany pops
Add alter, and tweak naming to make for slightly easier compatibility with SML/NJ map
For foldli/foldri, avoid using T.foldli/foldri because they have to reconstruct the key; instead do our own counting. Also fix incorrect index passed to f in the slice foldli/foldri functions (they were passing the array index rather than the slice index).
Use a datatype to make the types less interchangeable
Rename the trie-map function "modify" to "alter". The term modify is used in the Basis Array for a map-like mass update function, and as this is now implemented in our PersistentArray as well, the term had become rather confusing.
Added tag 1.0 for changeset 9f9d287bbb52
Correction - now only "most of" the same api
Caps a bit shouty now we have formatting
Fix example code (api changed here some time ago)
Update README and copyrights
Implement foldl/foldrRange directly, in addition to foldli/foldriRange
Add some more of the typical Array functions to PersistentArray (find, modify)