Ship speed High Delta

[GoogleCodeExporter]

Add a new sanity check (or within the ship speed check) to detect spikes in 
ship speed as per the High Delta check. This will catch situations where 
measurement times are filled in retroactively and don't take measurement gaps 
into account - this leads to speed sequences such as:

20, 21, 20, 20, 92, 20, 21, 22

They can be within the allowed speed threshold but still be bad.

Original issue reported on code.google.com by [email protected] on 8 Oct 2014 at 10:15