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. 
Another reason not to join with ampersand is that [it is a valid character in an email address](http://en.wikipedia.org/wiki/Email_address#Local_part)