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