Make blaze.testing into a script

Provide a simpler way to run the test suite in one line with `python -m blaze.testing`.

The documentation is updated to reflect this (although the old way still works).  Also, importing ucr inside blaze/ts/ucr_dtw/__init__.py seems to fix import errors that I get with the line `from blaze.ts.ucr_dtw import ucr` when running the tests with `python -m`.