GeoDms 15.9.0

This release has simpler versions of discrete_alloc that allows for allocating land use with claims that have the same partitioning:
discrete_alloc_np or no partitioning at all discrete_alloc_sp

Also, Qt is upgraded to 6.8.0
Known issue: #814, fixed in v15.10.1
Known issues: #838 and #841: consider using v16.0.2 or later, or v15.4.0 when aggregating values of an empty domain