As a lifter, I want Ironlog's Active Workout screen to move me through a workout flow, so that I don't have to think about what exercise to do next.

[bstauff]

The Active Workout screen should provide a guided experience. We want to move lifters through the various stages of their workout:

Warmup -> Main -> Supplemental -> Assistance

However, Ironlog does not currently have any concept of workout flow.

A workout flow should encapsulate the idea of moving from Warmup -> Main -> Supplemental -> Assistance