Added --disable-model-fitting configure option to turn-off model-fitting features and to allow compiling SExtractor without requiring the ATLAS and FFTW libraries.
Version number pushed to 2.12.0.

Fixed X/YMODEL_WORLD issue.
Increased CLEANing margin for model-fitting.

Fixed several issues related to image and weight copy prior to fitting.
Fixed bug with symmetric models.
Fixed issue with new FFT planning scheme.
Pushed version number to 2.9.5.