Begin refactoring the frontend
Broken state, checkpoint commit
Fix some pretty-printing
Refactor types and pretty-printing
More pretty printing fixes, and core AST changes
Buggy layout, and remove the old renamer
Fix the layout state machine
Big refactor

 * Start reworking the parser
 * Change the unification implementation
 * Strong partition between parsed syntax and core syntax
Change the way that debuggin output works
Replace undefined with panic
Better block parsing
More parsing
Pretty-printing wibbles
Update build instructions
Handle setup.sh being run multiple times
Formatting wibble
Change the way that source annotations work

Use Located, instead of replicating its functionality on every AST element.
More parser work
Parse row types
Many frontend changes