Updated auconfiguration .m4 files, including MKL autoconfiguration.
Added proper correction of model subsampling to MODELS,-MODELS,SPHEROIDS and DISKS check-images.
Added Eli Rykoff's fix to discard sources with NaNs in the fitted positions.
Improved debug info for memory allocations in FFT and FITS libraries.
Improved vectorization in FITS data transformations and FFT-based convolutions.
Fixed issue with ASSOC_TYPE NEAREST.
Pushed version number to 3.0a8.