Tor 0.2.3.5-alpha is out

Tor 0.2.3.5-alpha fixes two bugs that make it possible to enumerate
bridge relays; fixes an assertion error that many users started hitting
today; and adds the ability to refill token buckets more often than
once per second, allowing significant performance improvements.

Security fixes:

• Bridge relays now do their directory fetches inside Tor TLS
  connections, like all the other clients do, rather than connecting
  directly to the DirPort like public relays do. Removes another
  avenue for enumerating bridges. Fixes bug 4115; bugfix on 0.2.0.35.
• Bridges relays now build circuits for themselves in a more similar
  way to how clients build them. Removes another avenue for
  enumerating bridges. Fixes bug 4124; bugfix on 0.2.0.3-alpha,
  when bridges were introduced.

Major bugfixes:

• Fix an "Assertion md->held_by_node == 1 failed" error that could
  occur when the same microdescriptor was referenced by two node_t
  objects at once. Fix for bug 4118; bugfix on Tor 0.2.3.1-alpha.

Major features (networking):

• Add a new TokenBucketRefillInterval option to refill token buckets
  more frequently than once per second. This should improve network
  performance, alleviate queueing problems, and make traffic less
  bursty. Implements proposal 183; closes ticket 3630. Design by
  Florian Tschorsch and Björn Scheuermann; implementation by
  Florian Tschorsch.

Minor bugfixes:

• Change an integer overflow check in the OpenBSD_Malloc code so
  that GCC is less likely to eliminate it as impossible. Patch
  from Mansour Moufid. Fixes bug 4059.

Minor bugfixes (usability):

• Downgrade log messages about circuit timeout calibration from
  "notice" to "info": they don't require or suggest any human
  intervention. Patch from Tom Lowenthal. Fixes bug 4063;
  bugfix on 0.2.2.14-alpha.

Minor features (diagnostics):

• When the system call to create a listener socket fails, log the
  error message explaining why. This may help diagnose bug 4027.