Json : filtering for special characters

@wallacio : I have no error on MODX log when using the output filter tojson, such when I’m using the :htmlent output filter

@halftrainedharry : effectively, I’m using this json template at the “point template” of GeoTV addon.
But the add on works well with [[+pagetitle]] and all others regular TVs. I have access to them with a beautiful populated Json file