Documentation does not include a link to the recordings of the IJCB tutorial

I was giving the tutorial about the biometric recognition framework at IJCB 2017, the recordings of which are available here: https://www.youtube.com/playlist?list=PL-M6OZEM9v0FXfgvarnrpTMhURafZbXwp

For some reason, they never made it into the documentation of this package. I think, we should change this.