New Project: graphhopper #83
* entry in js/data.json: introduction text and license info from https://github.com/graphhopper/graphhopper
* logo combines (comparatively) high-res image header.png (cut out just the letter g) and the green background of favicon.ico, both from graphhopper.com, used lanczos interpolation and +70/127 contrast (gimp) (color,alpha) to enlarge it to the minimum acceptable size of 128×128