Add Legend
Add Legend

This commit adds an auto-updating legend to the map.

It removes the requirement of having user defined jenks for each
field, using the simply statistics library to calculate these
automatically.

We likely want to style and position this differently,
but that decision can be made by the visual designers.

DCActionforChildren/dcaction,gggodhwani/state_of_children_in_india,jotok/dcaction,gggodhwani/state_of_children_in_india,jsan4christ/dcaction,caiterade/dcaction,jsan4christ/dcaction,gggodhwani/state_of_children_in_india,caiterade/dcaction,caiterade/dcaction,DCActionforChildren/dcaction,jotok/dcaction,caiterade/dcaction,gggodhwani/state_of_children_in_india,DCActionforChildren/dcaction,jotok/dcaction,jsan4christ/dcaction,jsan4christ/dcaction,jotok/dcaction,DCActionforChildren/dcaction