Numbas LTI provider v2.11

[Christian Lawson-Perfect]

I've just released version 2.11 of the Numbas LTI tool provider. This release finally fixes the authentication problem when launching a Numbas resource embedded inside the VLE, instead of in a new tab. For browsers with strict cross-site security policies, it shows a button to open the resource in a new tab.

This version also includes a translation into German, thanks to Ulrich Görtz, and a summary table on each resource's dashboard, showing the feedback and availability settings.