Fix TrackAnalyzer thread names

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Allow filtering tracks by their spot's quality

Just like with the speed, we allow filtering by average, minimal, maximal,
median quality and by the standard deviation.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge pull request #27 from fiji/track-quality

Allow filtering tracks by their spots' quality