Release Name: AutoSeg_3.2.1_linux64

BUG: If no AUTOSEG_HOME variable was set, autoseg was running into a SEGFAULT due to a bad memory allocation for a C-string.
BUG: WarpImageMultiTransform was not packaged.
BUG: The processing loop was including pre- and post- processing steps.
BUG: Error message is shown if tissue atlas directory does not exist or contain no tissue segmentation probability map.