Filter frequencies by date url params

This turned into something of a rabbit-hole, but hopefully it's useful. Adds a date-picker to the top-right that filters `marketplaceCatalog` to only apps created within the date range specified.

![thecount-datepicker](https://cloud.githubusercontent.com/assets/71928/3821386/df0c9bce-1d0b-11e4-94f9-99c9a90a6f71.gif)