Don't forget running workers during cross-host PID collision
Work around GC silliness w.r.t. missing BeginTimestamp/EndTimestamp fields
Handle lat/lng=0/0 in GC waypoint download
Allow for SumDuration in place of SumElapsedDuration for laps
Specify py3k-ready Dropbox SDK in requirements (fixes  #20)
Retry GC auth during activity list if required
Fix mismatched activity stats with stationary GC activities
Change GC to using requests' sessions