uhd: fixes to instantiating UHD devices to set the antenna and subdevice properly (patch from Sam Bretheim).
uhd: change examples to use new stream api
uhd: added subdevspec option to UHD examples and sets antenna based on option.
uhd: updating examples to use args and better default for all UHD examples; also fixed the wfm_rcv blocks to use new PLL constructor.
uhd: Moved USRP analog TV receiver examples to gr-uhd/examples. They seem to run with the UHD, but I can't really test them since there's no NTSC signals around...