The first 4 of those should be fixed in my pull request. The last two I'm not entirely sure what the comments mean/what needs changing...

lib/matplotlib/tests/test_category.py
160:        # Image test would fail on numpy 1.6

is just that numpy1.6 doesn't support unicode and it's a unicode test. That comment can be removed now. And while editing that file, TestConvertToString should also be removed.

lib/matplotlib/colors.py
179:    # Python 2.7 / numpy 1.6 apparently require this to return builtin floats,

colors is weird 'cause that try catch is just to test if what's passed in is a floating point. I think the idea is that the c is expected to have been a numpy float array, and that's why it's being cast to a builtin float (as in 170). You may be able to remove that statement 'cause in theory other types were already captured, (and also remove the cast in 170)... though you may possibly need to put in a c = np.asarray(c, dtype=float) before 170 (possibly in a try/catch).

Basically something breaks later (on Py2.7+numpy1.6) if a tuple of numpy floats (rather than builtin floats) is returned. See 2fe2c26.

In fact I don't think that the version that starts with try: c = np.array(c, float) is much better (in fact, it requires additionally checking for ndim == 1), so perhaps you may just as well remove that comment without doing anything.

As a side note, either implementation suffers from the fact that the cast to float doesn't error when a string is passed in (as in plt.plot([1, 2], c=(".5", ".5", .5, .5))) but I don't think it's really worth checking that.