Vein of Galen classifications added

This is getting fun… I now added two frequently used classifications for vein of Galen malformations. Both are added to the new NeuroMind database, and now visible on (the beta version of) NeuroDSS.com.

The first one is the Lasjaunias classification, which divides them into choroidal and mural types (see on NeuroDSS).

The second one is an older classification by Yasargil (see on NeuroDSS).