Add consensus method 18 to the list in dir-spec section 3.8.1
Changes for proposal 215

13 is now the minimum consensus method; 1 is no longer required.
Add proposal 237: All relays are directory servers by Matthew Finkel
Merge remote-tracking branch 'nickm/bug10163_spec'
Mark proposal 215 as implemented, closed.
Specify how Guard Fraction voting should occur.
BadDirectory flag removal (#13060)
Merge remote-tracking branch 'sebastian/bug13060'
Bring more proposal 220 sections in sync with implementation
Update proposal 228 to reflect implementation status
rend-spec-ng: Link to Nick Hopper's proof of the keyblinding scheme.
Note that we will be dropping the "protocol" lines sooner or later

(See ticket #13593)
Documenting HEARTBEAT controller signal.
Update proposal 220 voting process to be actually secure

This makes it mirror the existing voting process, and ensures that
the results are equivalent once everybody is updated.
Merge branch '220_evolution'

This branch reflects changes I've needed to make in proposals 220 and
228 to reflect what's sensible or implementable (as far as I've found
while implementing them).
Document what we mean by "PEM format".

Closes ticket 13042
Document more networkstatus parameters.

List the ones I don't know how to document.

Try to find the version in which each one first appeared.

Closes #12888
Writing down possible values of reason string for 13212.
Merge remote-tracking branch 'rl1987/feature9503'
Set default value for bw weights if absent from consensus.