Refactor series by lead animation logic

[bikegeek]

Extracting the 'TODO' in the create_animated_gifs() method in series_by_lead_wrapper.py (as added by Jim Frimel):

TODO:

                # Fix animate_cmd so it does not require run_inshell
                #  to work.
                # It is working as is, ideally we do not require
                # run_inshell
                # The issue has to do with multiple files in the directory
                # when using the wild card. If only one file exists
                # then the command will run ok without run_inshell.
                # You can repeat the issue
                # by removing run_inshell keyword in the call below and
                # running examples/custom_series_by_lead_all_fhrs.conf use case.
                # no animated gifs are created.
                # convert: unable to open image
                # .... No such file or directory
                #  @ error/blob.c/OpenBlob/2712.
                # convert: unable to open file
                # convert: no images defined

[georgemccabe]

This was completed with work for #310