user module deleted

Sorry for two different modifications in one pr. This one fixes following things:
- ~~jpgraph (class for charts) has been included again. At this moment I couldn't found 2.x version on the web like INSTALL says. Mentioned url leads to 404. Setting up a local copy of this page is already bloody difficult - there's no need to complicate it more. Also I don't think that removing class form repository really makes sense.~~

- user module removed. In every combination of project and language I've tried "Users" tab is empty. If so, we're one step closer to clean up that mess.