DOC: Fix auto doc builds.

This is mainly just cleanup. I now redirect all stderr and stdout to files instead of doing a redirect from cron. One change had to be made to resolve a path through a symlink, since it's now run from a symlink in an anacron job. It will run every day or the next time this machine gets turned on, instead of having to leave it on all the time. 

I thought about redirecting the results of the docs build to its own file and inserting it into the success e-mails. That way we can see the doc builds logs. I can also just push it to sourceforge with everything else instead. Let me know if this is desirable.