[GraphHopper] javascript compatibility with LibreJS

[mtsio]

Hi,

Since the javascript code for graphhopper/maps is free (as in freedom),
it would be nice if LibreJS could validate properly the code. LibreJS is
an add-on for firefox based browsers that detects and blocks non-free
non-trivial javascript code
(https://www.gnu.org/software/librejs/index.html). There are guidelines
on how to do this
https://www.gnu.org/software/librejs/free-your-javascript.html.