Re-named readPixelData to pixelData in rereadDICOMFile() in order to keep backwards compatibility with readDICOMFile(), which will be removed eventually.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rigorous@326 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Moved dicom2analyze() and dicom2nifti() to a separate file.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rigorous@327 edb9625f-4e0d-4859-8d74-9fd3b1da38cb