Destroys the KeyMap instance and removes all handlers.
@param {Boolean} removeTarget True to also remove the {@link #target}
function(removeTarget) {
        var me = this,
            target = me.target;

        me.bindings = [];
        me.disable();
        if (removeTarget === true) {
            if (target.isComponent) {
                target.destroy();
            } else {
                target.remove();
            }
        }
        delete me.target;
    }