Convert para_recv to lopsub.

Convert para_recv to lopsub.

This converts the gengetopt parser for para_recv to lopsub format,
replacing the ggo file by a lopsub suite.

The conversion is rather simple because para_recv does not have
a config file parser and because changes to the build system are
small because we already link para_recv with -llopsub due to the
recv_cmd suite.