resolve ticket 32842

replace hard coded exclusion of authority tor26 with three
lists that during checks determine which authorities to not
a) check reachability for
b) check presence in consensus for
c) request and validate documents from

correct defect where router-line IPv4 OR address was not
checked for reachability

eliminate Python 3 exception by truncating array index
expression result to integer (further 2to3 revisions
applied during testing but not committed)