remove plaintext UPGRADING (.pod added by Ask)
removed a diff block from docs/config.pod
TcpServer: optimize DNS lookups for PTR

a. don't use search path (/etc/resolv.conf)
b. explicitely specify PTR in query request
move Auth-Results header to Original-Auth-Results

this was in a sub, commented out as a TODO to delete them. Instead of deleting, move the Authentication-Results header on incoming messages to the Original-A-R.
STATUS: removed -dev comments
Changes: updated with 0.93 changes