add incidents as geojson, hex bin shp, and mbtiles

Figured a few more data formats never hurt (and hex bins are cool). Quick version up [here](https://a.tiles.mapbox.com/v4/drewbo19.i282koj3/page.html?access_token=pk.eyJ1IjoiZHJld2JvMTkiLCJhIjoiWlpRb2lYUSJ9.aT3CQyI2_wYzqKPDqjgvyw#12/38.8921/-77.0202)

![screen shot 2014-10-09 at 12 03 12 pm](https://cloud.githubusercontent.com/assets/7108211/4579573/1a4f943a-4fce-11e4-97ce-084141444c9e.png)