Switch to a slightly faster pretty printer.

Improves performance of smten compiler a little bit.
Slightly more cleanup of pretty printer.

It's maybe a tiny, tiny bit faster now.
Pretty print (\a -> (\b -> ...)) as (\a b -> ...)
Pretty print tuples prettier.
Remove dead code for tracking exports.
Change how we "addimport" in the plugin.

In preparation for shortening the names we use for local qualification.
Use shorter qualified names in generated code.

Improves performance of smten compilation: 16s down to 14.5s in my test case.
Reduces size of generated code: 6.1M down to 2.3M in my test case.
Makes it easier to read the generated code.