WIP: feat(category): keep category selection on marker selection. 

#217

![keep_category 1](https://cloud.githubusercontent.com/assets/2622152/5569239/7d7dfc04-8f75-11e4-9bf7-9b3d7e7231a8.gif)

or better
``this.setActiveCategory = function(categoryId) {``

``this.removeActiveCategory = function()``