Since Tor 0.2.9 has been unsupported since January, 0.3.5 is the
oldest supported version, and its features constitute the oldest
recommended feature-set.
This patch updates these recommendations:
DirCache=2
Support for consensus diffs.
New in 0.3.1.1-alpha.
HSDir=2
Support for v3 onion service descriptors.
New in 0.3.0.4-alpha.
HSIntro=4
Support for Ed25519 intropoint authentication keys.
New in 0.3.0-4-alpha.
HSRend=2
Support for rendezvous cells longer than 20 bytes.
New in 0.2.9.4-alpha.
Link=5
Link padding and link padding negotiation.
New in 0.3.3.2-alpha.
LinkAuth=3
Ed25519 link authentication.
New in 0.3.0.1-alpha.
