Pull from upstream; changes to 'main.py' conflict with GENER work

[aufdenkampe]

Looks like respec@fcc2ee8 (main.py -- better handle subscripts for naming timeseries from external sources) from last Friday may have conflicting code with the new GENER code.

@ptomasula, can you resolve this merge conflict?

[aufdenkampe]

@tredder75, I see that you just merged the GENER stuff from @ptomasula into your branch with commit b3b2435.

There's a commit from @PaulDudaRESPEC that I just noticed that has a minor merge conflict that you'll want to resolve (with @ptomasula) before too long. See below.

[ptomasula]

@aufdenkampe @PaulDudaRESPEC
This was a pretty simple merge conflict to resolve. Paul Duda's work was on the get_timeseries function. The GENER required moving get_timeseries function to the utilities.py file to avoid a circular reference. That's why there was a merge conflict.

I merged in Paul Duda's update and then moved the updated get_timeseries and expand_timeseries_names function to utilities.py. This resolved the merge conflict and I've confirmed the model code still executes for our GLWACSO test case.