travis tests

[tolgayapici]

as i was looking at the failure messages on travis tests, I realize that none of the tests for testing different versions of numpy actually uses the version in the config file.
for a similar reason, in the dithering branch and in my pull request, one of the tests is failing because numpy version 1.13 only works for Python version 2.7 or >= 3.4.

[dkirkby]

@tolgayapici Can you give a bit more detail on the issue here? If I look at this recent travis log which is configured to use numpy 1.10, I see, for example:

$ export NUMPY_VERSION=1.10
...
The following NEW packages will be INSTALLED:

    mkl:   11.3.3-0     
    numpy: 1.10.4-py35_2
...
Numpy: 1.10.4
...

It looks like the test is using the specified version.

[weaverba137]

Aside from determining which numpy version is being tested, hopefully at least some tests are using 1.13 & 1.14. 1.10 is getting old at this point.

[dkirkby]

We are currently testing numpy 1.10, 1.11, 1.12 and "prerelease". I agree this should be updated but that's a separate issue, so I am closing this now.