Support for additional Connector/C API functions

With PEP-249 DB API only it's not possible to use all of the MariaDB API features, so
we need to provide additional methods which will be mapped to the corresponding Connector/C API functions:

Driver methods

Functions which doen't need a valid connection are methods of the driver.

• mysql_client_info
• mysql_client_version

Connection methods

Functions which require a (valid) connection are methods, stters or getters of Connection class

• mysql_autocommit: connection->autocommit()
• mysql_change_user: connection->user
• mysql_change_db > connection>database
• mariadb_cancel
• mariadb_reconnect: connection->reconnect()
• mysql_real_escape: connection->escape_string
• mysql_get_server_info: connection->server_name
• mysql_get_server_version: connection->server_version
• mysql_get_socket
• mysql_kill: connection->kill()
• mysql_ping: connection->ping()
• mysql_reset_connection: connection->reset()
• mariadb_get_optionv
• mysql_thread_id: connection->connection_id
• mysql_warning_count: connection->warnings

Cursor methods

Functions which require a (valid) connection are methods, stters or getters of Cursor class

• mysql_stmt_warning_count: cursor->warnings