CLN: remove docstrings from a handful of tests for consistency and nose -v output
BLD: travis, run nose with -v for more visibility
Merge pull request #6110 from y-p/PR_test_cleanups

CLN: Eliminate handful of test docstrings, use nose -v on travis
TST: add tests for old version of numexpr
BLD/CI: add numexpr==1.4.2 to build wheels
CLN/TST: DRY skip_if_no_ne
CI: cd to tmp to check encoding