Allow readimagecallbacks to try reading from the specified resource even if SoInput can't find it. Makes it straightforward to load textures from Qt-resources when using Quarter.
Allow readimagecallbacks to try reading from the specified resource even if SoInput can't find it. Makes it straightforward to load textures from Qt-resources when using Quarter.

Alexpux/Coin3D,Alexpux/Coin3D,Alexpux/Coin3D,Alexpux/Coin3D