#586 background jobs need to be cached in WW, not PE

[Lee Worden]

There's a dumb mistake where ProjectEngine uses $wgMemc to cache its list of background jobs' statuses, before filtering on particular project names, and returns filtered lists from it when requested by WW. But PE isn't supposed to use any $wg or $ww variables, because it should be able to run separately from WW.

So it should be returning the unfiltered list and letting WW cache and filter it. Or at least degrade gracefully and return the data without caching if $wgMemc and the other stuff isn't there.