Add keyword for watching TCP ports on remote machine

Add keyword for watching TCP ports on remote machine

This keyword gets a TCP port number, a state (LISTEN or
ESTABLISHED are the most useful but other states produced
by netstat may be used) and a process name. It then runs
netstat, greps through its output and reports the number of
occurences of a line mentioning the port, state and process.

An instance where this is needed was found in the BGPCEP
suite and transformed to use the new keyword. This can serve
as an example of how to use the keyword and additionally
serves as a test that the keyword is correct.

Change-Id: Ica59958e9b5ade564904a1725e9ef77154f84317
Signed-off-by: Jozef Behran <jbehran@cisco.com>