Client reports time as a float: store as such

Not sure there is an issue for this, sort of related to #2844.

Anyway, a long time ago, I changed the client to report floats to the nextgen server. It looks like the server basically accepts floats, casts to float anyway, but then stores the result in an int. This changes the storage to float.

I tested with the latest client: it correct shows 2.7s or whatever (I think the single digit is dropped for more than 10s or similar but anyway, this is a detail about display not storage).