Check lower base limit in base_repr.

[nbeaver]

A minor fix to ensure the range is as expected. (This is my first pull request, so let me know if I missed something in the protocol.)

[jaimefrio]

It would be nice to add a test that the error is properly raised somewhere here. Also, since you are working on this function, the docstring comment on it only handling positive numbers seems to be wrong, would be nice if you could fix that too. Otherwise, LGTM.

[charris]

Should squash the commits. Use `git rebase -i HEAD^^' in the branch and follow directions, then force push to origin.

[charris]

Also needs a test for raising the error. Should go in numpy/core/tests/test_numeric.py.

[rgommers]

@nbeaver could you please address the comments? It would be good to get this PR merged.

[nbeaver]

@jaimefrio @charris I have squashed the commits, fixed the docstring, and added the test as requested. There was some kind of merge problem, but I rebased the recent master and was able to fix it.

@rgommers Thanks for the reminder.

[charris]

Thanks @nbeaver .