Faster test_save_3d test.
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
Merge pull request #369 from cowlicks/faster-tests

Speed up 3 slow tests.