Update usage statement for Python.  Note that -s, -d, and -e are unimplemented.
Update usage statement for Python.  Note that -s, -d, and -e are unimplemented.

RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix