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

Summary

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

include/ccaosdb.h

@@ -265,9 +265,17 @@ typedef struct {
   void *wrapped_transaction;
 } caosdb_transaction_transaction;
 
+/**
+ * Create a transaction on an existing connection.
+ *
+ * This transaction has to be deleted manually by
+ * caosdb_transaction_delete_transaction() later on.
+ */
 int caosdb_connection_connection_create_transaction(
   caosdb_connection_connection *connection,
   caosdb_transaction_transaction *out);
+int caosdb_transaction_delete_transaction(
+  caosdb_transaction_transaction *transaction);
 int caosdb_transaction_transaction_retrieve_by_id(
   caosdb_transaction_transaction *transaction, const char *id);
 int caosdb_transaction_transaction_retrieve_by_ids(
@@ -302,9 +310,10 @@ typedef struct {
   char **version_id;
 } caosdb_entity_entity;
 
-int caosdb_transaction_result_set_get_entity(
-  caosdb_transaction_result_set *result_set, caosdb_entity_entity *entity,
-  int index);
+int caosdb_transaction_result_set_at(caosdb_transaction_result_set *result_set,
+                                     caosdb_entity_entity *entity, int index);
+int caosdb_transaction_result_set_size(
+  caosdb_transaction_result_set *result_set, int *out);
 
 typedef struct {
   void *wrapped_property;