Support for high resolution maps with UMN Mapserver

[pka]

For requesting higher resolutions, a WMS server dependent paramenter has to be passed as custom parameter. When you pass a higher MAP_RESOLUTION to UMN Mapserver, you have to pass also scaled WIDTH and HEIGHT to fix scale calculation. But the requested image is not scaled down to the display size in Jasper.
Best solution would be adding a parameter "DPI" to the component which does pass the correct DPI parameter and scaled WIDTH and HEIGHT values and scales the received image down.