giving a try at merlin
added types for the interpreter
- added lookup function to retrieve a variable's value from the state
- added types for constants
- added function to type a constant
added apply function to evaluate operators if types are compatible
added -annot to cflags
any expression can be parenthesized
call the interpreter at the end
added .gitignore file
rm .annot files too upon clean
indentation change only
some more tests
deleted "optimizations" on boolean expressions since they allow
type errors to creep in ("False && 1" gets accepted, for example)
gave a shot at the interpreter
corrected .gitignore