Add an option to convert double-precision attributes to single

main.cpp

@@ -2667,6 +2667,7 @@ int main(int argc, char **argv) {
 		{"empty-csv-columns-are-null", no_argument, &prevent[P_EMPTY_CSV_COLUMNS], 1},
 		{"convert-stringified-ids-to-numbers", no_argument, &additional[A_CONVERT_NUMERIC_IDS], 1},
 		{"use-attribute-for-id", required_argument, 0, '~'},
+		{"single-precision", required_argument, &prevent[P_SINGLE_PRECISION], 1},
 
 		{"Filtering features by attributes", 0, 0, 0},
 		{"feature-filter-file", required_argument, 0, 'J'},