Added files for conversion using fdf header

load_fdf reads in data from an fdf file as both binary and header data.
parse_fdf_header loads data from the fdf file header into a useful
strucutre.
process_fdf_folder, takes a folder of fdf files, and attempts to
rebuild a nifti image using NifTi and ANALYZE Image
http://www.mathworks.co.uk/matlabcentral/fileexchange/8797 using the
information within the header for each file, rather than attempting to
glue data together using filenames.