BUG: python-netcdf4 version 1.1.0 supported.

With version 1.0.9 of netcdf4-python, the method of accessing data in 0-dimensional arrays changed to be more like NumPy.  This required minor changes to Py-ART.  For additional details on the change see [issue 220](https://github.com/Unidata/netcdf4-python/pull/220) of the netcdf4-python repository.