More configs.

Adding after and before flags to be passed to git-log.

Adding gravatar_dir flag.

Adding glob flag so that repos can be matched by perl glob.

Adding flag to skip repo fetching.
Fixing fetching so that we get the log from the remote branch.
Also adding the ability to figure out what repo, and branch, master is
tracking for getting the git log.

Adding flag to skip retrieving gravatars.

Now calculating seconds per day based on range of actual commits, not
requested dates (tightens up the video if there aren't any commits in
the first, or last, days).

Dropping mp constant rate from 1 to 23 (1 minute videos are now around
10MB).

Change-Id: I03d14d9beba9867ef9100d64259e04dbc3e35a37