UDAF shouldn't use uint64_t variables storing its output as regr_count() and distinct_count() do

regr_count() uses uint64_t for a counter that is returned using boost::any. However MDB's allows to return only: INT, DECIMAL, REAL and STR from UDAF. The boost::any = uint64_t operations sets the boost::any internal policy to uint64_t in mcsv1sdk::mcsv1_UDAF::evaluate()(e.g. in RowAggregationUM::calculateUDAFColumns) so the revert operation in SetUDAFValue() can't deduce the type correctly.