Confluence upgraded to 5.1.3, Java to 1.7, Jira to 6.0

Confluence 5.0.x has a bug making the edtior close to unusuable in Google Chrome 27, which was named stable today.

Therefore we just upgraded clazzes.org to Confluence 5.1.3 which solves the problem right away.

Due to a weird problem of the confluence installer (net not found in java library path), and after good results from upgrading Java on other hosts, I also upgraded Java to 1.7.

Using the momentum, Jira was upgraded too and is now at 6.0.