Add round_trip_counter and tests.
Make fill do 1*len(view) roundtrips.

Previously was 2*len(view) roundtrips.
Reduce the number of round trips for DistArray.from_localarrays

Now reduced to 0, 1, or 1 per engine. Depending on the arguments.
Add tests for DistArray.from_localarrays
WIP: Fix TestDnpyFileIO with remote cluster

Also refactor it a little.
WIP: Fix TestNumpyFileLoad for a remote cluster
Merge pull request #373 from cowlicks/fill-roundtrips

Make fill do 1*len(view) roundtrips.
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.
Faster test_save_3d test.
WIP: Factor out engine_temp_path.
speed up test___init___ by using smaller data ((100, 100) -> (5, 5))
Speed up test_from_global_dim_data_uu with smaller data

30 element array instead of 120.
Test speed ups in test_distarray by reducing roundtrips.

speed things up by replacing for loops over arrays with calls to
.toarray(). Which still tests that the array can be indexed, but it
pulls it to the client and does it all on the client instead of
remotely.

This change affects:
    * test_from_global_dim_data_irregular_block
    * test_from_global_dim_data_bu
    * test_from_global_dim_data_uu
    * test_from_global_dim_data_bc
    * test_irregular_block_assignment
Add from_localarrays exception test.
Fix TestHdf5FileLoad.
Shorten some tests, remove some cruft.
Covert to {setUp,tearDown}Class for efficiency.