3D NIfTI Data Viewer

3D NIfTI data viewer based on the work of Jimmy Shen (#8797)

A Nifti 3D Viewer
based on the work done by Jimmy Shen(#8797)
Added some new features:
1 Open files from a tree view file browser (Menu: File -> File Browser)
2 Support scroll wheel to change view
3 Click hold and move left button to change view, instead of clicking multiple times
4 Adjust windown/level using right button (current axis) or both buttons (all axes)
5 Now load and show example MRI T1data, if no parameters passing in i.e view_nii();

Example:
%To run the viewer:
view_nii;