Add some information about the associated bundle to the child products in the cart details. This is necessary to know for example which was the price option picked for a given download when we want a custom site count / expiration date for licensing.
Updated as requested in the pull request discussion (make it lighter)
Covering some edge cases where options may not be set.
Merge pull request #1990 from marvinlabs/master

Enhancement to function edd_get_payment_meta_cart_details