Fix unittests that fail with numpy 1.9

This seems to be due to some very subtle changes in array precision,
so I am swapping assert_array_equal for assert_array_almost_equal.

The occurance of failures on a point release is unsettling, but this
at least keeps the tests informative.
Fix Python3 bootstrap arg test
Type safety
Merge pull request #292 from mwaskom/fix_numpy_tests

Fix unittests that fail with numpy 1.9