ENH: Update CornerAnnotation extension

This updates the CornerAnnotation extension to
871e9798adc1e65ead54f33bc2ac758e518eedcd.
Merge pull request #773 from ayamada0614/update-CornerAnnotation-4.3

ENH: Update CornerAnnotation extension
Merge pull request #2 from Slicer/4.3

4.3 Merge 10/6
ENH: Add HeterogeneityCAD
Merge pull request #775 from vnarayan13/4.3

4.3 ENH: Add HeterogeneityCAD Module
Merge pull request #4 from Slicer/4.3

Merge pull request #775 from vnarayan13/4.3
ENH: Add HeterogeneityCAD

Remove Add_Subdirectory(Testing) from CMakeLists.txt
Merge pull request #777 from vnarayan13/4.3

4.3 ENH: Add HeterogeneityCAD Module
Merge pull request #6 from Slicer/4.3

Merge pull request #777 from vnarayan13/4.3
BUG: Declare all scripts in module in CMakeLists
Merge pull request #779 from vnarayan13/4.3

4.3 BUG: Fix OpenCAD Generic Test errors
Merge pull request #7 from Slicer/4.3

Merge pull request #779 from vnarayan13/4.3
BUG: OpenCAD CMakeList directory reference
Merge pull request #785 from vnarayan13/4.3

4.3 BUG: Fix OpenCAD CMake directory references
ENH: Addition of IntensitySegmenter as a Slicer extension

IntensitySegmenter is a simple tool that segments an image according to intensity value. It is mainly used to segment CT scans using the Hounsfield scale but the ranges of intensities and their corresponding labels can be specified in an input text file. For more information, refer to [1] and [2]

[1] http://www.slicer.org/slicerWiki/index.php/Documentation/Nightly/Extensions/IntensitySegmenter
[2] http://www.nitrc.org/projects/dentaltools/
Merge pull request #798 from fbudin69500/add-IntensitySegmenter-4.3

ENH: Addition of IntensitySegmenter as a Slicer extension