Changed data format to `{ x, y }` where `x` is time in milliseconds

This PR includes the previous ones (some of them were rejected, so this might require manual merge).
Great idea, but why not get current UNIX time once, upon starting the binary, and then just add one point per some 0.1 seconds? You could start 10 seconds from the past, getting the first 100 points right away.

The idea is to have ```data[i]``` consistent for fixed indexes.