use all pagegenerators options for protect.py

- remove "nosubcat" option which was never implemented
- include revision: 0b888f24b532d54ee93574632b34c162fbe77ba0
  made by Merlijn van Deen:
  mysite was not defined. pywikibot.handleArgs is guaranteed to
  return a list (as opposed to a generator) after parsing all
  global arguments (such as -lang and -family). This means it's
  safe to call pywikibot.getSite immediately after handleArgs,
  but before handling local arguments.
- pageName is extracted from command option handled
  by pagegenerators if availlable. Otherwise we ask for the
  message.
- -images option is deprecated. -imageused from pagegenerators is
  used. We just append the right option command to the option list
- docu replacement from pagegenerators

Change-Id: I6e2b6b85670a28e24c50f6da9cb6b3db236f78b5