Better error message in prepare_base.
Fixed memory leaks in NcABCClusterNCount and NcClusterAbundance. Some new additions and more stable ABC code.

Added log function for NcmSerialize.
Better implementation of NcmABC and NcABCClusterNCount.
Changed summary statistics in NcABCClusterNCount.
First functional version of NcABCClusterNCount.