[bugfix] compat -imagelinks is -imageused in core
[bugfix] compat -imagelinks is -imageused in core

- reorder summary input so -help message will be shown if
  no generator is given.
- -file option does not expect pageName

Change-Id: Id5eb5dd6c42d024bc9758475d82641fcb396977f

icyflame/batman,darthbhyrava/pywikibot-local,npdoty/pywikibot,Darkdadaah/pywikibot-core,trishnaguha/pywikibot-core,xZise/pywikibot-core,happy5214/pywikibot-core,h4ck3rm1k3/pywikibot-core,VcamX/pywikibot-core,npdoty/pywikibot,emijrp/pywikibot-core,magul/pywikibot-core,TridevGuha/pywikibot-core,hasteur/g13bot_tools_new,h4ck3rm1k3/pywikibot-core,happy5214/pywikibot-core,hasteur/g13bot_tools_new,valhallasw/pywikibot-core,hasteur/g13bot_tools_new,magul/pywikibot-core,jayvdb/pywikibot-core,smalyshev/pywikibot-core,wikimedia/pywikibot-core,jayvdb/pywikibot-core,PersianWikipedia/pywikibot-core,Darkdadaah/pywikibot-core,wikimedia/pywikibot-core