Allow passing arguments to <options> methods

[mpchadwick]

Allows you to write a method like this when working with dropdown EAV attributes

<?php

class Mpchadwick_GridControl_Model_Utility
{
    public function getDropdownAttributeLabelOptionArray($attribute)
    {
        $attribute = Mage::getModel('eav/config')->getAttribute('catalog_product', $attribute);
        $options = $attribute->getSource()->getAllOptions(false);

        $map = [];
        foreach ($options as $option) {
            $map[$option['value']] = $option['label'];
        }

        return $map;
    }
}

Then you can re-use it whenever adding a dropdown attribute

<?xml version="1.0"?>
<gridcontrol>
    <grids>
        <productGrid>
           <manufacturer>
                <add>
                    <header>Brand</header>
                    <type>options</type>
                    <index>manufacturer</index>
                    <options>mpchadwick_gridconfig/utility::getDropdownAttributeLabelOptionArray('manufacturer')</options>
                </add>
                <after>name</after>
            </manufacturer>
        </productGrid>
    </grids>
</gridcontrol>

There might be other use cases I'm not thinking of...