Merge branch 'maint-0.3.5' into maint-0.4.0

  o Minor bugfixes (relay):

    - Avoid crashing when starting with a corrupt keys directory where

      the old ntor key and the new ntor key are identical. Fixes bug 30916;

      bugfix on 0.2.4.8-alpha.

  o Minor bugfixes (logging, protocol violations):

    - Do not log a nonfatal assertion failure when receiving a VERSIONS

      cell on a connection using the obsolete v1 link protocol. Log a

      protocol_warn instead. Fixes bug 31107; bugfix on 0.2.4.4-alpha.

  o Major bugfixes (torrc):

    - Stop ignoring torrc options after an %include directive, when the

      included directory ends with a file that does not contain any config

      options. (But does contain comments or whitespace.)

      Fixes bug 31408; bugfix on 0.3.1.1-alpha.

  o Minor bugfixes (testing):

    - When testing port rebinding, don't busy-wait for tor to log. Instead,

      actually sleep for a short time before polling again. Also improve the

      formatting of control commands and log messages.

      Fixes bug 31837; bugfix on 0.3.5.1-alpha.

  o Minor bugfixes (logging):

    - Rate-limit our the logging message about the obsolete .exit notation.

      Previously, there was no limit on this warning, which could potentially

      be triggered many times by a hostile website. Fixes bug 31466;

      bugfix on 0.2.2.1-alpha.