Licence text still mentions "Development Seed, Inc."

(not directly related to, but obviously prompted by reading, https://github.com/mapbox/osm-bright/issues/116 )

Obviously not the most serious issue in the world (should have no practical effect on usage) but I thought I'd better mention it :)

Search the repository for the licence text mentioning "Development Seed, Inc." and read the surrounding file to confirm the current project attribution. Update that attribution as appropriate, then verify no remaining occurrences of the outdated name remain.

Written by the indexing model from the issue text.