simplified docstrings, minor bugfixes
convert integer format to int32 for NETCDF3_CLASSIC
also convert integer types for NETCDF3_64BIT, strange...
pass tol parameter from the class to the axes, if defined
fixed __array__ for VariableOnDisk
prepare release note
fixed __getattr__: if attribute present in the class, return it
nloc now works fine for both Dataset and DimArray
additional tests for nloc indexing
ignore tol for non-numeric axes
bugfix: cast int to float when 'float32' is assigned
improved cast rules for Axis
added a rename_keys method to Dataset
added rename_axes similarly to rename_keys, for completeness
fixed metadata (pre-) definition in GeoArray coordinate axes.
bugfix: _FillValue attribute when writing to netCDF is now interpreted
appropriately.
more informative message when netCDF4 fails to open a file
added reindex_axis and reindex_like methods to dimarray.Dataset
Have DimArray and Dataset deriving from an OpMixin class
==> add basic operations to Dataset
added DimArray.interp_axis and DimArray.interp_like methods
added pre-sorting step to interp_axis