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.

Changed CONCENTRATION_MODEL to SPREAD_MODEL.
Added SPREADERR_MODEL measurement (currently a crude estimate).
Optimized FFT calls.
Set PSF_NMAX to 2 by default.