Changes as requested on #2717

[Alex-developer]

• Allow the number of images to process to optionally be passed as an argument (to flow_runner.py ?). The default can remain at 10.

Added --flowtimerframes option to flow-runney.py Default is 10

• Add a variable to allsky/variables.sh to define the directory, e.g., ALLSKY_FLOWTIMINGS. This will make it easy for check_allsky.sh to find the directory.

Added the following variables
ALLSKY_FLOWTIMINGS="${ALLSKY_TMP}/flowtimings"
ALLSKY_FLOWTIMINGS_DAY="${ALLSKY_FLOWTIMINGS}/day-average"
ALLSKY_FLOWTIMINGS_NIGHT="${ALLSKY_FLOWTIMINGS}/night-average"

• How will check_allsky.sh know the names of the files? Should other variables be added, e.g., ALLSKY_FLOWTIMINGS_XXX ?

See above

• allsky/allsky.sh should rm -fr "${ALLSKY_FLOWTIMINGS}" so we know any files are from the current instance of Allsky.

New option --cleartimings added to flow-runner.py. This is called from allsky.sh to clear all timing data

• Please make times stored in the files in integer milliseconds.

Values are now ints