User interface additions

[pmbarrett314]

I love your site! I use it when teaching sorting algorithms, and I think the visualization really helps at least some of the students to grok the concepts where just looking at code might not. I would love to see some additions to the UI to make it easier to work into a lecture.

Specifically, a pause button would help so I could freeze some of the algorithms at a specific point and explain what's happening. You could even build off of this by showing some debug info on the values and allowing stepping backward and forward, but just a simple pause would be really helpful

I'd also love some way to control the speed other than changing the input size. Some of the n^2 algorithms tend to be a little slow and lead to just awkwardly waiting on the sort to finish, where some of the nlogn algorithms tend to be a little fast where it can be hard to see the emerging patterns.