Breadcrumbs fix

This fixes the issue with breadcrumbs.

Essentially what this does it will try to include the following values as cache tags if possible:

product_id
category_id
page_id

This means that when viewing a product in a new session only product_id would be counted, while if you had selected a category and then a product you would get category_id and product_id due to the layered filtering. All of this has been tested and the same product viewin in separate sessions, one through layered navigation and one stand alone (just using the url key) both get the appropriate breadcrumbs (ie. the one viewed directly by it's unique url key will only show "Home / Product Name" where as through layered navigation you would get "Home / Category Name / Product Name").

This has been tested with products, categories, products viewed through the layered navigation, and cms pages. I have measured that data and made sure that the cache is released when it's supposed to be and that the appropriate cache is always used for the block.