[Discuss-gnuradio] raw frame transmit functionality added to usrp_server

[George Nychis]

I added functionality for transmitting a raw frame to the usrp server now also.

A couple things:

I am not sure what to initialize 'tag' to in the header, I'm not sure we have a concrete 
plan for this field yet?  So I set it to 0 for now.

I need someone (aka. Eric ;)) to check over how I am extracting the samples from the 
m-block data and placing them in to the usb packet.  I am not 100% sure I am doing this 
correctly.

Thanks!

- George