* updated VTK library to VTK 6.1
* modified some startup parameters
fixed minor issue with ROI3DArea / ROI4DArea and ROI5DArea.
Merge branch 'master' of https://Stephane-D@github.com/Icy-imaging/Icy-Kernel.git into develop
Merge branch 'master' of https://Stephane-D@github.com/Icy-imaging/Icy-Kernel.git into develop
* minor fix for better memory clean in some case with IcyCanvas.
* better headless support
Merge branch 'master' of https://Stephane-D@github.com/Icy-imaging/Icy-Kernel.git into develop
* fixed serie selection bug on multi serie image loading (regression).
* fixed headless initialization issues (regression).
* completed new VTK 6 library loading.
* removed IcyLogo component.
* some changes made to the importer interfaces.
* 'open' command can now open any type of file (not only
image) with available FileImporter.
* 'import' command allow now to open data with available Importer.
* Canvas3D:
 - name changed to VtkCanvas
 - added new Volume visualization option (as GPU Raycasting).
 - separated volume rendering in dedicated class.
* updated VTK library loading for unix system.
* added VtkSequenceVolume and VtkImageVolume classes.
* SequenceUtil: added toGray(..), toRGB(..) and toARGB() methods.
* IcyCanvas: automatically enable all LUT channel when position C
is set to -1 (all channels).
* VtkCanvas:
 - added bounding box, rules, axis display.
 - better update of VTK objects (safe).
 - many improvements, bug fixes and cleanup.
* VtkImageVolume: many improvements and bug fixes.
* VtkUtil: new methods to create volume image and colormap.
* minor change to get rid of the weird IncompatibleClassChangeError
which can happen on some OSX distribution.
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