Several important changes:
(1) coeffmod_OMS_element.py: rewrote most of the code to implement ordp / relative precision (now code is closer to the OMS code in dist.pyx).
(2) coeffmod_OMS_families_element.py:
      - implemented relative precision
      - fixed _cmp_ (though still not happy with it because of how comparison of power series is coded in sage)
      - wrote solve_diff_eqn !

Minor changes to the other 7 files
Move dist.c, dist.pyx and families_util.pyx out of target of sage source code (so that sage will compile).
Some examples/tests:
(1) tests.sage: a sage script that runs some tests on the code. (currently tests solving diff eqn)
(2) code_for_tests_in_old_code.sage: some code to run in our old code to generate examples that we can check our new code against
(3) Examples.sage: minor updates
A patch to apply on a clean installation of sage 5.7.