libobs: Export obs_properties_apply_settings

I didn't think it would ever need to be exported, but this function is
actually useful for applying settings to properties (to call all of
their update callbacks based upon the settings) without necessarily
having to have an object associated with it.

libobs/obs-properties.h

@@ -101,8 +101,11 @@ EXPORT obs_property_t *obs_properties_first(obs_properties_t *props);
 EXPORT obs_property_t *obs_properties_get(obs_properties_t *props,
 		const char *property);
 
-/* used internally by libobs */
-extern void obs_properties_apply_settings(obs_properties_t *props,
+/**
+ * Applies settings to the properties by calling all the necessary
+ * modification callbacks
+ */
+EXPORT void obs_properties_apply_settings(obs_properties_t *props,
 		obs_data_t *settings);
 
 /* ------------------------------------------------------------------------- */