Placed the conditional statements for selector existence WITHIN the document ready calls, so that they actually worked as intended.

Created overlayLeaflet file
Added map-leaflet selector to CSS for map selector. Created leaflet styles css in case that is needed
Attempted to modularise the JS but was having problems with the ordering of when variables were declared and defined. As such, all the Leaflet code is now plugged into the same anonymous function, which is sad.

Displaying the unstyled data on the map, woo.