add ordering of indexer

[brosenberger]

as the smart category indexer writes entries into the table catalog_category_product the indexer should run before the indexer of the catagory_product_index to include all changes generated by the smart category.

the ordering could be changed within the module by adding following snippet to the indexer.xml:

<indexer id="catalog_category_product"> <dependencies> <indexer id="smartcategory_product"/> </dependencies> </indexer>

additionally the according category-product index should be invalidated (i guess by using the indexerregistry?)