Fix bad handling of maximum function arity.
Reestablish pep8 compliance.
Fix default optimization level.

Was (nothing), now is -02.
Also remove the need of -DNDEBUG which was pretty confusing.
Fix typing of weird recursive case.
Improve OpenMP support.

Support taskwait and test it.
Parallel Fibonacci implementation.

Typical showcase of task feature, here with sequential/parallel
trade-off.
Improve type inference for dictionaries.
Fix bugs in type inference in presence of subscripts.

Handle cases such as:

def foo():
    d={ 1 : set() }
    d[1].add("str")