* changed the file handler typ for the target from and input file handler (using initializeInputFiles) to a registration pipe file handler
* created a minc atom for xfmconcat, and moved the code to create a pipeline stage there
* moved RotationalMinctracc to the minc atoms (from hierarchical_minctracc)
* added the posibility of using a mask for RotationalMinctracc
* added the xfmconcat minc atom
* added some very basic error checking to getBlur. In this function it is possible that a blur file or gradient file is being retrieved that has never been created. In that case, a "non existent key access error" will occur. This catches it and gives a bit of detail as to why the code fails.
* renamed getHighestResolution to getFinestResolution in order to make the return value of this function more intuitive.