Added support for Mac OS X and other variants of Unix that do not use GNU version of readlink and sed.

- The BSD version of readlink does not support the -f option.

- The BSD version of sed does do not support specifying “-” for the filename when receiving input from standard input.

- Improved performance and UNIX portability of pre-commit-uncrustify by removing the use of sed and grep when determining that committed file's extension matches the ones to be sent to uncrustify.
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.
Added -l option (language override) to uncrustify command line.

- Added -l option (language override) to uncrustify command line is needed because the internal langue selection thinks is not always accurate.  For example .h file extension returns CPP, but could be C or OC.
Merge pull request #1 from m2orris/master

Added support for Mac OS X and other variants of Unix that do not use GNU version of readlink and sed.