[ANN] opentrack-2.3-prealpha-20141018_1

- output axis selection from input for each tracker, no need for
  per-tracker support anymore.
- settings, including mappings, take effect immediately -- that
  is, before OK pressed. pressing cancel reverts them as usual.
- ui mildly redesigned
- pitch +-180 allowed, EZCA mode gets the knife
- ypr xyz all default to linear 1:1 0->180 mapping for new configs
- FreePIE UDP receiver tracking source support
- PT tracker dynamic pose resolution removal, it never worked right
- aruco tracker even better than before
- kalman and ewma filters improved and continue being improved
- maintainability updates, including better functionality you
  don't notice

- bugs that were reported on github issue tracker were fixed