o Minor features:
    - Bridges now track GeoIP information and the number of their
      users even when pluggable transports are in use. These
      statistics are reported in their extra-info descriptors like
      normal bridges do. Resolves ticket 4773.
    - Bridges now track the usage of their pluggable transports and
      report statistics in their extra-info descriptors. Resolves
      ticket 5040.