[maps.soton] Indoor Map App

[Christopher Baines]

Just came across this:

http://clement-lagrange.github.io/osmtools-indoor/#lat=50.93645&lon=-1.39579&z=20&id_building=3301274&id_level=3490222

While currently, leaflet-soton shows the inside of all buildings at a
particular level, this tool uses the different per building approach.

It also allows interacting with lifts and stairs, which is something I
want to add.