Cosmetics, cleanning.
PEP8
Loading abs and M_PI from libc.math
Defining twopi when loading for speed.
Adding boxcar and blackman windows.
Cleanning the code.
maud.py should be pure Python.

maud.py before tried to load some Cython functions, but not anymore.
New submodules distance & cdistance.
Removing distance related funcs from maud.
Distance related funcs moved away from maud.
Creating window_func_scalar.pyx
Creating test_window_func.py
Organizing window_func.pyx.
Updating path to haversine functions.
Ignoring more stuff
Organizing window_func.
Improving test_haversine
Improving cdistance with haversine 1D & 2D.
Profile switcher for window_func.pyx
Improving test_haversine.py