Split swarming tests out of integration tests.

Build is now running integration tests without swarming. Swarming tests have been broken out as a sibling folder to `integration` to make it easier to split with minimal changes to the test runner and cmake configuration. 

Fixes #1325.

Coupled with https://github.com/numenta/nupic.regression/issues/11.
Not a removal, a move. I moved all the files in `tests/integration/py2/nupic/swarming` into `tests/swarming/py2/nupic/swarming`.