Suggestion: submitAX.py command line option support

[DavidAntliff]

It would be helpful to support the specification of a student's email address and assignment token on the command line, to help reduce needless retyping and support integration with IDEs (for configuring submit macros).

E.g.

python submitA1.py ---email username@email.com --token ABCDEF12345678

If omitted, the program would prompt as it does now.

Also, consider allowing specification of the parts to submit:

python submitA1.py --part 1
python submitA1.py --part 1 --part 2
python submitA1.py --part all

Easily implemented with argparse and I can submit a PR on A1's script if it will be considered - please advise.

Extended support might include lists and ranges, but this is less important:

python submitA1.py --part 1,2,3   # list
python submitA1.py --part 1-3     # range