control-test/node.cc: pre-allocate for the proper number of module inputs
control-test/node.cc: updates for change to Signal-based message handlers
control-test/node.cc: print all argument errors encountered

Previously we would find an improper IP address, report it, and promptly
exit even if the user also provided an invalid port-number string; now we
report for both cases as necessary, then exit [in case of _any_ invalid
argument].
control-test/README.md: added build instructions.
Merge branch 'master' of github.com:dubotics/robocrisp-base