Sign Instance
GET /data/api/signs/107/?format=api
http://labasi.acdh.oeaw.ac.at/data/api/signs/107/?format=api", "sign_name": "A", "abz_number": "579", "meszl_number": "839", "image_1": "http://labasi.acdh.oeaw.ac.at/media/sign_img/sign_579.bmp", "image_2": "http://labasi.acdh.oeaw.ac.at/media/sign_img/sign_001_VQMYMDP.bmp" }{ "url": "