added roi based img normalizer.

deprecated old image normalizer
fixed minor bug in twovaluestocellnodemodel
minor fix in ImgNormalizerNodeFactory
WIP
WIP
First version of ImgNormalizerNodeFactory
added filling methods
fixed enumutils
inverter now works on ROIs
fixed bug in inverter
inverter, thresholder and normalizer with ROI

old implementations are deprecated
added descriptions
added some comments
code-cleanup
new libraries
Using copy method of image instead of operation

	* Operation assumes same iteration order, this may go wrong in the
	* case of ImgViews
	* Using native copy method of incoming img/imgview
new libraries
removed error message for missing cells

	* this is not an error, this is a warning
removed error message for missing cell

	* we handle this, so this is not an error to the user
	* we give a warning
Merge branch 'master' into roi_nodes

Conflicts:
	org.knime.knip.base/src/org/knime/knip/base/nodes/proc/ImageNormalizerNodeFactory.java
	org.knime.knip.base/src/org/knime/knip/base/nodes/proc/InvertNodeFactory.java
	org.knime.knip.base/src/org/knime/knip/base/nodes/proc/ThresholderNodeFactory2.java
	org.knime.knip.core/src/org/knime/knip/core/util/EnumListProvider.java
	org.knime.knip.core/src/org/knime/knip/core/util/EnumUtils.java