Enable cache_eap module by default
Refer to cache_eap authorize method, not authenticate
Added dict_attrbyparent()

Which gets a DICT_ATTR based on a parent reference, and an attr number

This is so that any magic of playing with attr/vendor is hidden
inside of one function, rather than being in multiple places
Look for extended attrs before RFC format ones
VP_TRACE using hex values for VID / attr

It's easier to read
Decode extended TLVs correctly.

This uses the new dict_attrbyparent() API to avoid doing magic
on "nest".  The code becomes a bit easier to read.