PY3K/TST: cast range to list and random seeding

Python 3 Related
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The code used a range call to generate a list of elements, and then
access elements from that list. Changing from python 2.7.x to 3.x you
cannot do this as range becomes a generator, thus I've added a cast to a
list.

Testing
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Using the built-in seed function from the random library would generate
different values between python 2.7 and py3k. Thus I've changed the
seeding and random operations to use numpy's which is consistent across
python versions.

Note that along with this I had to change the results of the tests,
however these will be consistent now.
STY: Fix a few stylistic issues

Some of the errors being raised by flake8 have been fixed here:

- hommola_cospeciation had an unused import, this has been fixed by
  adding the function to the __all__ variable which was previously
  missing.
- Unused math and assert_raises imports in the hommola and
  test_hommola.py files.
Merge pull request #1 from ElDeveloper/cospeciation

Fixing travis failures