trunk: various script changes to better support Mac OS X. Avoiding the '-T'...

trunk: various script changes to better support Mac OS X.  Avoiding the '-T' option to 'cp', and the '>/dev/stderr' syntax in awk, which is only supported by GNU awk.  Also providing an alternative to 'du -b' for getting file sizes, to failover to 'stat' on Mac

git-svn-id: https://svn.code.sf.net/p/kaldi/code/trunk@4877 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8