Irrationality of version numbers

Just to show that release numbers are figments of one's imagination, here's a point release with lots of new stuff and cleanups.

• New colour gradients (--gradient NAME), red (red), red/green (rdgn), yellow/orange/red (yor)
• Efficiency mode display (requires --efficiency option)
• Major internal cleanups, in preparation for:
  • Unification of bbl2kml and otx2kml into flightlog2kml
  • GUI (don't hold your breath, but it's a possibility)

Please see the front page README; there are some new settings and behaviours.