non-group-files will be loaded much faster now

since now, e.g. with tiff files, each and every file tried to examine all
files in the same folder to check whether there exists a metadata file
in the same directory. this check was performed on setSource,
even if m_groupfiles was disabled.

Signed-off-by: dietzc <christian.dietz@uni-konstanz.de>
Merge branch 'Annotator' of https://github.com/knime-ip/knip into Annotator
- Small Bugfix
- Added setColor method to interface
- Provided  implementations of new methods in the LabelingColorTable Interface
- Added hashCode() implementation to ExtendedLabelingcolorTable and ListLabelingColorTable
- Added new constructor to allow the restriction of the selectionMode of the AnnotatorLabelPanel
- Changed LabelingAnnotatorTool and propagated changes to implementations
- Split DeletionTool into two seperate tools
- Modified Events corresponding to Tool actions
- Switched View to new classes
- Added delete-functionality to the manager
- Cleanup in the Manager
- Removed output of the Node (for now)
- Fixed errors in AdditionTool, no functionality yet