Got rid of libtim

Initial timing problems with imap was coming from some conflict within
libtim. Extracted only needed modules from libtim. From zern.py:
zernike_rad, zernike, noll_to_zern, zernikel, calc_zern_basis,
fit_zernike, calc_zernike. From im.py: mk_rad_mask.

Adjusted code for python3, there is no longer a .has_key(), xrange ->
range, and called reduce() from functools.