Modified mount.sh so it works in OS X as it does in Linux. Note that there is more that can be done on this script like mount only sd or cf image and eject all of the EOS_DIGITAL volumes but for now it works fine.
Changed shebang in two scripts that I missed in my last pull request.
Added OS X specific tests for mounted disk image in run_canon_fw.sh. (Already saved me several times)
Todo - maybe sometime in the future add a preflight check or modify install.sh to check if the system has the required programs installed and arm-none-eabi-gdb in the path.