Merge proposal 222 (eliminate timestamps) into the specifications

Also update it with actual decisions and parameters.
Fix typo.
Merge branch 'implement_prop222'
Update proposal index with 222 closed
add DUMPGUARDS command
Rename DUMP->DROP, add a warning
Merge implemented proposal 218 into control-spec.txt.
Merge proposal 221 (stop using CREATE_FAST)
reindex proposals
Document what we use for KH when we're doing ntor.

KH is part of the material derived from the KDF during the onion key
process.

In the TAP handshake, KH played two roles: it was sent by the server
towards the client to prove that the server was able to complete the
TAP handshake, AND it was included as part of the
RELAY_ESTABLISH_INTRO message to make it impossible to replay a
RELAY_ESTABLISH_INTRO from one circuit on another circuit.

With the ntor handshake, the first value of KH was removed.  But we
still needed a shared, circuit-specific value for hidden service
code to work.  This value is taken as an additional 20 bytes from
the KDF.  It wasn't documented in the spec, though.  Adding it here.
Don't enumerate event types in section 3.4

When adding an event type we expect spec authors to edit both section 3.4 and
4.1.x. This is error prone...

  https://trac.torproject.org/10085

Dropping the redundant listing of event types and simply citing 4.1.x.
Describing CONN_BW's ConnType

Our new CONN_BW events' ConnType enumeration is poorly defined...

  https://trac.torproject.org/10086

This is just a guess on my part for what it's supposed to be. I have *not*
trudged through the tor code to puzzle out how it actually allocates this
enumeration.
Fix a small mistake in pt-spec.txt.

Fixes #10090.
Be an insufferable pedant and hyphenate a phrase.
Merge remote-tracking branches 'atagar/10086' and 'atagar/10085'
Mark the dir-key-crosscert element as required.

This closes proposal 157.
Looks like Roger marked 213 as "should be marked Dead" without Deadening it. Deadening.
Mark proposal 146 superseded by 206
Mark proposal 217 finished. Still needs merging into spec
Merge remote-tracking branch 'public/finish_prop157'