Put client side modules in distarray/client/ and change imports.
move client.py -> distarray.py and change imports to reflect this.
move DISTARRAY_BASE_NAME into top level __init__.py

This is because dacluster should not have to impor distarray/client/ to
clean things up.
Fix circular import issue with distarray.py
client_maps.py -> maps.py. add __future__.absolute_import where needed.

Since the module distarray/client/distarray.py's name conflicts with the
package name we import `absolute_import` everywhere in the file.
rename client directory to dist
Remove cruft from bad rebase.
Move client tests to dist/tests/.
Fix a missed instance of client_map -> maps
Moves suggested by @kwmsmith
More moves and rebase fixes
Merge branch 'cowlicks-split-global-local'