Updates to set_config_value parameter

- add boolean parameter for set_configuration_value to specify whether
  the single config parameter change is is wanted to save immediately
  (usefull when changing multiple different values)
- rename set_cfg_value to set_config_value
- renamed get_cfg_value to get_config_value

Signed-off-by: Mika Laitio <lamikr@pilppa.org>