Started the normalization phase
Don't pass the Program around
Fixed specs
Complete normalizer method. Bootstrap now compiles again.
Handle require in normalize
Fixed type and codegen is_a?
Remove dead code that comes after a return, next and break
Fixed graph and print types
Expand defs in normalization phase
Simple def expansion for default arguments
Expand range literal in normalization. Fixed bug with type lookup in included modules.
Fixed normalization of && with is_a? when obj is not a var
Added TODO
Normalize case to a chain of ifs
Normalize code generated by macros
Added missing specs
Normalize regexp literals
Parse unless as Unless nodes and normalize them to if before type inference (more consistent for eventual API users :-P)
Parse string interpolation as a StringInterpolation node and normalize it before type inference
Missing unless normalization spec