Allow datacontext to return the real values for concepts and filters

![screen shot 2014-05-29 at 11 06 52 am](https://cloud.githubusercontent.com/assets/2774472/3119075/eb405cf4-e742-11e3-936a-7edb45d6961d.png)

What is returned when a filter is applied.

This will be used to apply styles to the filter display in filter.js 

Signed-off-by: Sheik Hassan <solergiga@yahoo.com>
Update comment for clarity. `Some values are represented by django models have...` doesn't make sense(at least to me).