[system] Ticker imprecision

[siteswapjuggler]

The ticker library deliver unperfect performances it varies for about 500 µs both ways. For a 20 ms ticker it varies from 19500 µs to 20500 µs.

I don't know if it comes from the other tasks delaying the ticker or from a inherent default within this library process... anyway 500 µs seems negligible for our application.

[siteswapjuggler]

Later measurement show a 0.005 % variation over the desired timing and the average value is very close to the desired timing.

I should now test different timing methods to found the best option among :

• delay
• elapsedMillis
• ticker
• metro