change test for no-mask to one which works when there is a mask
new method so outside objects don't have to access _inputs directly.
New special-case in __getitem__ to serve code which mistakenly does foo['coords'] when it should be
calling foo.coords().
Fix two names: plotall_id for plot sets 1 and 2, so that it will differ from plot1_id even when
there is only one filetable.  Names and ids don't work unless they're unique!  This probably is
needed for other plot sets as well.
- added lots of new cloud variables
- better error handling in stdvar2var
Minor improvements in error handling, line breaks, etc.
added some land diagnostics examples
fix a name conflict
For clouds, this sum shouldn't be weighted.
Correct and earlier oversight: add another cloud axis name to the reduction exclusion list
in plot set 5, vars_stdvar_normal_contours.
In reconcile_units, interpret no units as units of '1' ('fraction').  I may later remove this
feature if I think we don't need it.
Also, minor improvements to warning messages and comments.
fix a little bug - compare axis names with names, not with axes.
Define some general-purpose utility functions for interpreting and selecting regions and computing seasonal climatology
Add region functionality to AMWG plot set 5.

This requires adding region functionality to a couple of the
functions in reductions.py.

Note that region is implemented in the plot set as a class
attribute when the set is initialized, and can be called as
self.region.  Therefore it is not necessary to pass it to methods
in the function as an argument.
Delete set-specific method interpret_region, which is replaced by shared function in reductions.py
Merge pull request #27 from susburrows/susburrows/add_regions_support

Susburrows/add regions support