editarticle: move from optparse to argparse

Changes editarticle.py to use argparse, as optparse was deprecated in
 python 2.7/3.2.
Behaviour is identical to optparse except for a nicer help message.
Updated script_tests to account for the argparse requirement in python
 2.7.

Bug: T70617
Change-Id: I0614674840c96205fe7c8ff48e3bea1273a886cb
Merge "editarticle: move from optparse to argparse"