uhd

uhd: branch-less round for time spec convert to ticks

This fixes valgrind warnings with branching on unit'd values,
and possible exceptions thrown on bad unit'd values.

As it turns out, sometimes tick_rate was passed unit'd,
however, the value calculated was not of consequence....

Swap I/Q on transmit

uhd: add samples per pkt option to rx streamer

usrp2: firmware should reset dsp on icmp pkt

1) This should kill any streaming,
the previous calls would just stop continuous streaming

2) The breaks were changed to returns
to avoid reprogramming the framer.

images: include license file into image tarballs