Before switching to Angular UI Tree
Added Angular ui tree. Fucking Slow
Before adding angular ui tree: added bind once
Merged
After merge
Added removal of categories with no drugs from the tree
Switch to POJO Js Tree

Angular is too slow with event bindings when # of bindings grow > 2K.
Event libraries like 'once', 'bindOnce' do not work well.
On top the recursive directories for building trees, although fast
at first, bulge under heavy loads of DOM. Switching to POJO with Jade
templating seems to ease the problem, making the time rendering bearable.

Added POJO jsTree library to public/; added tree templates to partials/tree