Use page properties to find if a category is hidden

Bug: 65149

Added also:
     @pywikibot.site.need_version("1.13")
     def isEmptyCategory(self):

     @pywikibot.site.need_version("1.11")
     def isHiddenCategory(self):

New method Page.version() defined in order to use such decorator.

Change-Id: I349559ee93fae1c6f8832581ed774da965740539
Merge "Use page properties to find if a category is hidden"