Query Performance

This PR implements the options to disable the hitcounter and the publish up/publish down feature of com_content as discussed here: https://groups.google.com/forum/#!topic/joomla-dev-cms/LxfiHaOO9Fk

By making it possible to disable the hitcounter, we prevent Joomla from updating the #__content table on each pageview and thus invalidating a potential MySQL query cache.

By making it possible to either reduce the resolution of the timer of the publish up/publish down feature or even disabling that feature altogether, we keep having the exact same query over a longer period of time, allowing MySQL to use its query cache if necessary.