v2.6.7

Added PanSTARRS-1 astrometric reference catalog.
Fixed segfault when using large input "@"lists.
Restored initial ordering of fields after field grouping.
Fixed issue with decreasing MATCHing contrast in large sets.
DATE-OBS date and time now taken into account in epoch computation.
Pushed the hard limit for the number of references sources in Vizier queries to 100,000,000 per group
Fixed valgrind warnings (nothing critical)
Added --with-release configure option for setting package release number.