Testing error messages
Added pre-conditions for filter, some tests, and some notes
Added to the dictionary, started on types for functions.
Started on function type matching. It seems to work in repl, but doesn't work here for some reason.
Fixed the functions problem; added filtering out user namespace for now.
Added more cases for the type dictionary, added a message for converting to ISeq
Set up more reasonable testing; fixed some error-reporting issues.
Discovered a problem with IndexOutOfBounds exception that I don't understand.
Added more tests.