Add Duration To Tick Method Of `PendulumTicker`

[GGist]

Would allow our futures based runtime to utilize this, and any clients that dont want to call tick at exactly the tick duration, can just pass the duration since they last called tick, so that real ticks are managed internally.

Any clients that want to send a real tick can just call it with the tick duration.

[GGist]

Might not want to do this due to supporting situations such as #3 without some way to also query this leftover duration.