incompatible jpeg library between gd and mapserver

[assefa]

The gd-1.8.4 (compiled version) does not use the same jpeg library as the one 
used in mapserver.

The error produced when trying to load a jpeg file is : JPEG parameter 
struct mismatch.

The quick fix was to recompile mapserver without the USE_JPEG flag. 
The real fix is to recompile gd-1.8.4. Could not compile it yet on 
windows.

Personal refernece : look in folder msapps/jpeg_pb for test files.

[assefa]

The DM builds now use only the jpeg libarary found inside GDAL for all builds
linking with jpeg.