Configuration timeouts - 0 default doesn't work

[DavinChurch]

Some timeout values (e.g. HTTPCacheTime & IdleTimeout) are described as having default times of 0. But if they are removed from Server.xml the defaulting code (e.g. ConfigureServer[18-19]) blows up because it passes Dates.ParseTime a scalar '0' instead of a vector, and ParseTime can't handle a scalar.

This would probably best be fixed in Dates.ParseTime but just calling it with a vector would solve the problem.