Merge remote branch 'gnuradio/wip/udp_source_sink'

Merge remote branch 'gnuradio/wip/udp_source_sink'

* gnuradio/wip/udp_source_sink:
  gnuradio-core: update copyrights
  gnuradio-core: allow swig to handle exceptions in UDP source/sink
  grc: update UDP source and sink block wrappers
  Simplify USE_SELECT usage
  Return immediately when using d_residual.
  Defend against a peer that sends an invalid message length.
  Move initialization of select timeout
  Correct update of d_temp_offset (parallel construction)
  Identify memory leaks that occur on error conditions
  Use -1 as file descriptor "not open" value instead of 0
  Add additional conditionalization of networking includes
  Flush pending errors in gr_udp_sink on disconnect()
  Rework UDP source and sink, with incompatible API changes
  Updates to udp source/sink (select(), wait, cleanup)
  Discard data in gr_udp_sink until receiver is started.
  Use getaddrinfo in gr_udp_{source,sink}
  Changes to gr_udp_{source,sink} for MinGW
  Ignore ENOPROTOOPT return from setsockopt(SO_LINGER)