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

(it's still done the old way on my own fork because the commit was from the 6th March when the base version didn't match (now it can be merged, therefore this pull request) )