Trainable Weka Segmentation: added exception print trace.
Trainable Weka Segmentation: added log information when loading a classifier fails.
Trainable Weka Segmentation: fixed bugs in the GUI code.

Correct javadoc typos and add update help URL in the Settings dialog as pointed out by Johannes Schindelin.
Trainable Weka Segmentation: fix rank of threshold application.

This way one can apply those methods to a single threshold.
Trainable Weka Segmentation: added method to compute the precision and recall based on the pixel classification after warping (only for splits and mergers).