Remove unnecessary keyword from generics examples
Correct typos: INSTALL.txt, MzCOM, ffi/com
Make case-> reduce to -> when it can.
Allow prefix function arrow type
Add ->* type constructor for optional arguments
Abstract out function that checks ->* style types
Lift out `partition-kws` function into util module
Print ->* style types with ->* constructor

This recognizes the type for a function like
`regexp-match?` and will print it concisely.
Compress case-> types with ->* more aggressively
Use syntax classes to parse ->* type constructors
Add printing tests for ->*