Option to limit number of iterations

## Use Case

It would be nice to put a cap on the number of iterations - especially when not doing a final render, the keeping the number of iterations capped would allow a nice enough image to be drawn, but prefent the GPU from being used endlessly after the number of iterations has been reached.

## Solution

Add a new option to cap the total number of iterations when using the interactive viewer.

## Alternatives

_Please describe any alternatives you've considered, even if you've dismissed them_