Postpone recursive traversal and validate Access Descriptions

Postpone recursive traversal and validate Access Descriptions

1. It was traversing through children before the current
   certificate's validation was done. It's fixed now.
2. Adds validation of CRL Distribution Points, AIA.caIssuers and
   SIA.signedObject.
   Man, those requirements looked deceively small. It was a
   freaking mess.
   I'm not actually sure this is the final version of this code,
   because several argument lists grew too much for my liking.