Draft: API: remove UniqueResult, lower-case at, size for ResultSet

Summary

• Remove UniqueResult
• At and Size are lower-case now (ResultSet, MultiResultSet)

test/test_ccaosdb.cpp

@@ -115,8 +115,7 @@ TEST_F(test_ccaosdb, test_query) {
                                                       "local-caosdb-admin");
 
   caosdb_transaction_transaction transaction;
-  caosdb_connection_connection_create_transaction(&connection,
-                                                  &transaction);
+  caosdb_connection_connection_create_transaction(&connection, &transaction);
 
   int return_code(caosdb_transaction_transaction_query(
     &transaction, "FIND ENTITY WITH id=123"));