some wms servers lack a scalehint max attribute

I found a WMS server that lacks the max attribute in the scalehint element. According to the 1.1.1 WMS standard it's required, but I added a check for it so that it does not cause an error. 

The server that had the error is located at this url:
http://geodata1.nationaalgeoregister.nl/luchtfoto/wms

I informed them of the error, so it might get updated at some point.