Non-zero exit code and set -e bug, naming convention change, README update

- Fixed bug in canonicalize_filename.sh where set -e interfered with the trapping of a non-zero exit code from readlink -f.  The trap should have flagged that the -f option was not supported and the alternative method was to be used.  However set -e was causing the script to exit at that point.

- Changed the naming convention of the script canonicalizeFilename.sh and functions contained within to match the original body of work.

- Updated README to include the description of canonicalize_filename.sh.