Now need to implement GUI for that:

1) GUI should be done like DropShadow class implementation.

2) The new class should work with the three config classes:

psd_layer_effects_glow_common --- just a general pointer for handling
    glow configuration.

psd_layer_effects_outer_glow and psd_layer_effects_inner_glow --- specific
    structures for handling each effect. I'm not sure GUI need to know
    about it.