Updated timers, added forceNumeric

Timers are percent-based, but its simpler than earlier implementations

JoL trial types only accept numeric characters (as well as periods)

When a new trial is started, the first input is focused, but the page isn't scrolled down
Merge pull request #25 from TysonKerr/newTimer

Updated timers, added forceNumeric
**Timers are now more accurate AND use less CPU power