dataio tiff: fix TIFF metadata read and >2D data reconstruction

also ensure the TIFF metadata is saved for each part of the array of a multiple array
also now save the pretty printed version of the XML, for easier reading for the user if he needs to do it himself
dataio: clean up
dataio tiff: add support for reading back metadata from OME XML

not yet metadata from the channel and other indirect tags
dataio tiff: more metadata reading from OME-XML

the hardest is still to come