Preliminary implementation of a RESCALE_WEIGHTS configuration switch.

Added new ASSOCCOORD_TYPE configuration parameter for ASSOCiating detections either in PIXEL or WORLD coordinates.
Fixed sampling issues for Sersic, de Vaucouleurs and exponential model-fitting.
Version number pushed to 2.13.2.

Pushed version number to 2.13.1.

Added more complete headers to all files.
Clarified licensing issues.
Updated FITS library.
Updated configuration files.
Added configuration files to the list of data that get installed in ${prefix}/share/sextractor.
Added background offset and point-source model components: FLUX_BACKOFFSET,FLUXERR_BACKOFFSET,FLUX_POINTSOURCE,FLUXERR_POINTSOURCE,MAG_POINTSOURCE,MAGERR_POINTSOURCE.
Tweaked model-fitting convergence parameters.
Fixed catalogue source ordering/number issue in dual-image mode.
Pushed version number to 2.13.0.

Improved real-time display.
Fixed various issues with XSLT in double image mode.
Pushed version number to 2.11.0.

Improved processing time display.

Fixed error ellipse measurements in PSF-fitting (but works only for PSF_NMAX=1 currently).
Simplified PSF parameter handling (removed PSFDISPLAY_TYPE configuration option).
Simplified triggering of local north axis computation.
Allowed model axis ratios to exceed 1 to facilitate convergence.
Fixed alignment bug for symmetric models.
Restricted maximum allowed range for model coordinates.
Pushed version number to 2.10.0.

Removed singular matrix warning.
Added MATRIX_MODELERR measurement parameters.
Added DURATION_ANALYSIS measurement parameter.