Profile slow unit tests

When watching the builds, I have long noticed several very slow tests. Don’t know which of these it is or the cause – either a slow download or actual computation. That is, when the progress “dots” “walk” across the screen: https://travis-ci.org/cltk/cltk/jobs/514967233#L1919

To check for test times, here is a resource (note to self or whoever takes this up): install nose-timer (https://pypi.org/project/nose-timer/) and add --with-timer flag to nosetests the command.

Coming from #895 and #896 , which tried to help by telling Travis to cache directories. In these tests, I did not cache the ~/nltk_data dir, so this could be something to try as well, if in fact it is downloads slowing things.

[free-variation]

The difference in performance between the build and running tests locally might be related to the resources of the VM, e.g. slow I/O, at travis-ci.org

[diyclassics]

@free-variation Yes, good catch. The commit above adds the transcriber to setUpClass—in the short run this strategy may be a useful/worthwhile on for speeding up the travis builds.