Add missing optional attributes

Hi,

I was getting AttributeValidator ready for deployment in our environment and I found it wasn't displaying eduPersonPrincipalName.

I went through all the attributes in our (AAF and Tuakiri) attribute vocabulary and found there were overall 4 attributes defined in the vocabulary (as Optional) that were not being recognized by the AttributeValidator.

Here is an implementation - please feel free to merge or comment.  (I see you already list missing EPPN as your own issue - #7).

Cheers,
Vlad