E.g.:
<pragma-> show testcargs
<PBot> [global] testcargs: /code c11 printf("/say args: " ); while (*++argv) printf("[%s] " , *argv);
<pragma-> testcargs 'hello''world' 'how are 'you today
<PBot> args: [helloworld] [how are you] [today]
Previously, adjacent 'foo''bar' would end up as 2 args like [foo] [bar]. Now
they are properly concatenated into one [foobar] argument.
This also fixes the cases of whitespace being inserted after quoted arguments.
* replace heartbeat with health-check
* instead of steady stream of newlines every 5s, now awaits input
and responds with `vmstat` output
* more reliably use host/config/vm-exec.json to get libvirt domain name
for snapshot-revert, server address, serial ports, vagrant setting, etc
* use iptables/nftables to disable networking
* added guest/bin/disable-network-[iptables,nftables]
* added guest/bin/enable-network-[iptables,nftables]
* replace ugly ___OUTPUT___ texts in sh, bash, ksh, zsh languages
* documentation updates and tweaks
