Link to the Quartz Scheduler seems to be outdated

It seems that OpenSymphony has seen it's final days.

We still have a link in XWiki/SchedulerJobSheet which points to a generic URL. Changing the link to the actual quartz-scheduler would be better.
Since we use a very old version of Quartz (1.6.5) the link to the API for 1.6.5 has been remove, thus I am proposing to put the link to the documentation page.
Also, the link has some leftovers from 1.0 syntax