* added 3D, 4D and 5D rectangle ROI (available through code only)
* ROI:
 - fixed minor issue on subtraction operation.
 - fixed NOT boolean operation for 3D, 4D and 5D ROI.
* Canvas2D and VtkCanvas:
 - reset view with 'r' shortcut
 - reset view and palette with 'R' shortcut
* Loader:
 - better image auto ordering from filename when loading a group of file
 - better progress information when loading a group of file
* fixed minor refresh issue on histogram
* Sequence:
 - added getDefautColormap(..) and setDefautColormap(..) methods.
 - added getColormap(..) and setColormap(..) methods (user LUT)
* Colormap are now correctly preserved on channel extraction or remove.
* minor fix on the UndoManager.
* others minors changes.
Merge branch 'develop'