Allow completion of interactive commands and factor repetition.
Nix closure names, so they don't gunk up autocomplete.
Make display of types more useful in interactive mode.

Removes origin hints from types and makes the display of universal
quantifiers consistent with the input syntax.
Add origin information only to type error messages.
Rephrase type error messages.
Use correct library search paths in interactive mode.
Correct interactive line numbers sans implicit Prelude.