Fix Hipchat notifications in CI.
Ignore a virtualenv in local directory if you're got one.
Don't explode if received message is not a JSON array/object.
Reorganize docs so USB backend is more prominent.
Iterate through all available USB CAN translators until one is available.
Correct typo in name of LongitudinalAcceleration
Check if a measurement actually has states before iterating.
Add states for button events - doesn't handle action types, yet.
Remove FineOdometer - Odometer is now high resolution.
Remove another reference to FineOdometer.
Remove flag to openxc-dump that went to null-land.
Update Travis CI token for HipChat.
Fix YAML formatting in travis file.
Allow using callback functions that don't use kwargs.
Warn user if serial library isn't installed.
If message buffer is a string (e.g. from a trace file), convert to bytes.

Fixed #9.
Restrict openxc-gps to tracefiles.

We need to wait until the trace is compelted so we know to close the GPX file's
structure, so we wait for the trace playback to finish when creating a GPS log.

This isn't going to work well if you're using a VI directly, but I can't think
of a case when you would do that vs. recording a full OpenXC log.
Output GPX data as a string, not Python bytes.
Ignore test .gpx files.
Move pyserial and requests to optional dependencies.