Fix a bug in assignment when the rhs is an LValue
Add support for function definitions, function calls, and nested variable scopes
Improve step display during AstAssignment LValue unpacking
Make for loops use the new nested scopes
Get return statements and recursion working
Comment out unused number styles for now, since they're interfering with the grammar
Get complex boolean expressions working (and fix some grammar precedence errors)
Add array/dictionary access
Add support for metal objects