Complete api documentation

+1

This could be the API documentation, I had some issues with those hooks:

/**
 * Never triggered.
 *
 * @deprecated
 */
function hook_metatag_config_load() {
}

/**
 * Never triggered.
 *
 * @deprecated
 */
function hook_metatag_config_load_presave() {
}

/**
 * Never triggered.
 *
 * @deprecated
 */
function hook_metatag_config_presave($config) {
}

I didn't saw any point of the code where are called, so I marked then as deprecated. If it's true I think, they can be removed from the module.

I forgot to comment, I've also fixed the most of the coding standards issues on this file.

So I found hook_metatag_config_presave() but I'm not sure the other two still exist.

Committed.

Lets leave this open to continue improving the documentation.

Thanks :)

Will handle further improvements in #1466292: Document all Metatag's hooks.