WIP: optimization on displaying studies list

I got really tired of how slow is the studies display when having so many studies so I started working on https://github.com/biocore/qiita/issues/601. This is the initial optimization of /private/. I want to have some feedback before working on the others. 
Not sure what you mean -- you execute the three queries and get three lists back, which you then return.  The performance of anything beyond that (what did you have in mind?) will be highly implementation dependent.