Should esmlab functions return xarray objects for scalars?

[mnlevy1981]

• esmlab version:`2019.1.0
• xarray version: 0.11.2
• Python version: 3.6.7
• Operating System: macos 10.14.2

Description

As discussed in #28, confusion can arise when a scalar value is returned as an xarray object... for example, taking the weighted average of an array where the weights and array have the same dimensions. In those cases, it might be preferable to return just the values attribute of the xarray object.

What I Did

Had a conversation with @andersy005 that led to #28 and then thought more about what I expected to happen

[andersy005]

Resolved in https://github.com/NCAR/DIS/wiki/Meeting-Notes:-17-January-2019