You can now specify limits for specific apps,
and/or for the project as a whole.
Within each of these, you can specify limits on
CPU jobs, GPU jobs, or total jobs.
In the case of CPU and GPU limits, you can specify
whether the limit should be scaled by the number of devices.
Note: the enforcement of this is done in get_app_version(),
since per-resource-type limits may dictate what app versions
we can use for a particular job.
svn path=/trunk/boinc/; revision=21674