[Issues] imageview server

[W.J. Vriend]

Dear all,

We have updated the imageview server. This service is responsible for 
creating cutouts from fits files and converting fits files to png's. Not 
all code in the imageview server was thread safe. Therefor it could 
happen that making a cutout failed, or that the cutout was not of the 
intended region. These problems should be solved now.

Best regards,

Michiel Tempelaar
             &
Willem-Jan Vriend