Fixed setup.py so "pip install -e" works
Removed data copies from Dataset

data.copy() is not implemented if data is a netCDF4 variable, and in any case
it seems that we should always use views unless a copy is explicitly
requested.

Conflicts:

	src/polyglot/data.py
Switch dataset.coordinates values to variables

This makes it consistent with dataset.noncoordinates. If you want the old
behavior (values as dimension lengths), then you can just use
dataset.dimensions instead.
Rationalized copy methods and pylint cleanup

Conflicts:

	src/polyglot/data.py
Dataset.translate() can now optionally copy the object.

Fixed most unit tests, test_translate_consistency still fails.