Added xml Reading for other image types as well as Subject Hierarchy loading
Added xml-reading into SubjectHierarchyNodes.

 - Some paths are hard-coded and must be changed before compiling (s. SubjectHierarchyReadMe)
 - Sets up basic Subject Hierarchy (without paths, ...)
 - All images (up to now "image", "warped" and "vector") are loaded and associated
   to corresponding SubjectHierarchyNodes
 - Each "image" defines one phase
 - Indices are checked (only one image per index-value, only one warped image per phase,
   existing reference image)