collectors.ping: handle repeated icmp-send failures
collectors.ping: re-issue suppressed name resolution warnings after a reasonable delay
collectors.ping: fix for delays before sending pings being dependent on data polling bug
collectors.ping: use one socket for all pings and tests
collectors.ping: uniform output
collectors.ping: support IPv6 pings
collectors.ping: embed timestamps into sent packets, instead of keeping track of these locally
collectors.cgacct.memory: read "usage_in_bytes" counters
collectors.ping: better error reporting