I have found the Doceri app which looked to me very promising.
- screencast recorder included (that, for example, Goodnotes doesn't have)
- presentation mode (no toolbars appearing on the screen)
but, unfortunately, no way to import a pdf into the Ipad app and annotate it. To add this option, one should couple the Ipad app to the desktop app, that looks quite heavy to me. The major drawback of this is that my school has no license for Doceri.
Do you have any idea of an Ipad app that, having the specs mentioned above, also gives the possibility to import and annotate pdf ?