Start on some class type rep
Temp commit
More tmp
Tmp fixes to get things to compile
Get Class syntax working at basic level
Add more class type parsing tests
Add a few failure tests
Fix phase of import
Add duplicate checking and tests
Clean up object init and add support for get-field
Make Class type printing a little better

Still needs a lot of improvement, especially pretty
printing with line breaks
Purpose statement
Support #:extends clause with a class type
Fix existing uses of class types
Fix type-rep
Remove colons from type syntax

This was an awful choice.
Change #:optional? -> #:optional

Another awful choice
Missed a few class types
Add a class: that does preprocessing of class macros
Progress commit for class type-checking