balanceTags() should not be option dependent

[mdawaffe]

As a formatting function, balanceTags() should do just that - balance the tags. It's behavior should not depend on the use_balanceTags option. Whether the function is *called* should depend on the option.

Attached:

1. makes balanceTags() option agnostic
2. deprecates force_balance_tags()
3. creates wp_balance_tags() which calls balanceTags() depending on the use_balanceTags option.

#2650 suggested the same and offered a patch that maintained backward compatibility. This patch is cleaner but breaks backward compatibility for some plugins. The older ticket was rejected, but I think the idea should be reconsidered (hence this ticket).

[mdawaffe]

To be backward compatible, we could do essentially what #2650 suggested:

function balanceTags( $text, $force = false ) {
    if ( !$force && get_option('use_balanceTags') == 0 )
        return $text;
    return force_balance_tags( $text );
}

function force_balance_tags( $text ) {
    // old balanceTags code without option check
}

[mdawaffe]

backward compatibility method

[ryan]

(In [5805]) Make balanceTags() option independent. Props mdawaffe. fixes #4626