News: New addon tutorials

I've written and released 3 new tutorials that give examples and exercises for extending or modifying ocPortal, as well as helpful background information. The tutorials are designed to help people to get into the process of making ocPortal addons, and to tie into existing tutorials that we have.
Whilst deeply technical, I hope the tutorials remove any fear people have with developing for ocPortal. It's much easier than most other systems, and you can do it on the comfort of your own desktop PC.