Some bug fixes for CDRIO and add recv_with_header_blocking()

Signed-off-by: Rick Taylor <rick@tropicalstormsoftware.com>
Remove a pointless copy in CDRIO

Signed-off-by: Rick Taylor <rick@tropicalstormsoftware.com>
Catch empty message condition with CDRIO

Signed-off-by: Rick Taylor <rick@tropicalstormsoftware.com>