#13 Converting 3D files to 4D and vice-versa

[Cinly Ooi]

It is necessary to have the functions to process 3D files into one 4D file and vice-versa. The current thinking is to support using a text file (.txt ext), nii3dfiles1[0000] and nii3dfiles[0010-0100] to hold 3D filenames in a file, all nii3dfiles1NNNN for NNNN=0000 onwards, or all nii3dfilesNNNN for NNNN=[0010,0100]