WIP ENH: Multiple views of the same brain

Let me know if this is something people would be interested in. Maybe it should be called MultiView instead of MultiBrain because the idea is it's really just one brain...

From the command:
```
from surfer import MultiBrain
brains = MultiBrain('fsaverage', 'split', 'inflated', ['lat', 'med', 'ven'])
```
I get:
![Screenshot from 2013-03-15 17:54:34](https://f.cloud.github.com/assets/2365790/266155/5e2cb498-8dd4-11e2-95c3-c817b8478cce.png)

Also, does anyone know how to remove the Mayavi toolbar from these plots using code??? I've searched for hours trying to find a solution to no avail. It must be something simple, since it's possible to simply right-click and toggle the silly thing, but I can't figure it out.