* new image "cal_questionmark.png", will be used as a "modifier image"
  for "tempmaybe" category attribute
* recreated cal.png (and gif+xpm variants) with smooth lines

  See bbbike-aux/images/cal_questionmark.xcf for sources; needs special
  layer setting.
* reorder really-slow-checks targets

  Currently most likely target to fail is check-nearest, so run it
  first.
* ups, typo
* data update