WIP: Fix TestDnpyFileIO with remote cluster

Also refactor it a little.
WIP: Fix TestNumpyFileLoad for a remote cluster
WIP: Pull out the cleanup_file function.
Fix TestHdf5FileSave.test_save_block...

to work with a remote cluster.
Fix TestHdf5FileSave.test_save_3d...

to work with a remote cluster.

Also factor out `check_file` to a reusable `check_hdf5_file` function.
Fix TestHdf5FileSave.test_save_two_datasets...

to work with a remote cluster.
WIP: Factor out engine_temp_path.
Fix TestHdf5FileLoad.
Shorten some tests, remove some cruft.
Covert to {setUp,tearDown}Class for efficiency.
Add a note to the module docstring

regarding current assumptions about a shared filesystem.
`assert_array_equal` -> `assert_allclose`

in test_functions.py to make the tests pass with a remote cluster.
Merge branch 'master' into bugfix/remote

Conflicts:
	distarray/dist/tests/test_distributed_io.py
Merge pull request #375 from enthought/bugfix/fix-tests-with-remote-cluster

Fix tests when using a remote cluster