My € 0.02 from the Git crew: I can only underline what Darren wrote:
Personally, I think whatever is easiest for the student in question is best.
Let them decide. If the students prefer the Boost sandbox over GitHub, that's fine. However, I highly doubt it. At least the students I know are more comfortable with Git than with SVN these days. And GitHub has other benefits. Mentors actually don't need any knowledge about Git at all. You see the code on the website with syntax highlighting. You can comment on commits. You can add comments to individual lines in the source code. If you want to try out the project, you can download it as tarball or zip archive. Students will need to know how to commit changes and syncronize with a remote repository. You learn that here: http://try.github.io Ready? Shall we use https://github.com/BoostGSOC as a common place for all GSOC repositories?
So, students can assume that users have boost installed on their machine in a standard location, and can set up a separate git repository for their project. Great.
Right! Please spare the students with complicated setup. Let them concentrate on code. Also, please let them choose their favorite build system. cheers, Daniel