fix bindPopup for feature layer tutorial (#81)
fix bindPopup for feature layer tutorial (#81)

* create tutorial and copy over template

* add sections to tutorial

* complete draft 1 of tutorial

* made suggested copy edits

* update bind popup code

* update bindPopup function

jgravois/esri-leaflet-website,jgravois/esri-leaflet-website,Esri/esri-leaflet-doc