vcs: Add details about -u, -m parameters to commit Changes correspond to changes made to handout in previous commit.

vcs: Introduce commit with -u and -m parameters commit is now introduced with -u and -m parameters. This fixes a couple of problems -- 1) hg sometimes doesn't allow commits without username 2) vi(m) is the default editor -- most people can't use it (yet).

vcs: Fix tiny indentation problem in handout.