Replace parsing to regex to better match time=??ms

Following on from #18 here's an attempt at parsing (output[1]) with regex.

Handles sub 1ms pings, where windows prints < instead of =, eg time<1ms
Handles a minor different between unix and windows formats where unix has a space preceding the 'ms'
Have only tested sub 1000ms responses, unsure of OS's latency response format above 999ms ie 1000ms or 1,000ms