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.
Merge branch 'trainable-seg-gui'

Correct typos and update link in the GUI.