The parsed args container is passed to the run() function and friends
for convenient use. Sometimes, though, the base classes or umbrella
commands need to make use of it, too, even more so as they may define
command line arguments via add_arguments(). However, run() or _run()
or whatever is never called on them, neither any other callback, so
make args available to them as a member variable.
Signed-off-by: Jan Lindemann <jan@janware.com>