Hot-Reloading Causes working-keys to expand wildly

[JRJurman]

Summary

Since we don't totally reset the place of branchIndices when we finish rendering, it's possible to have the working-keys to constantly stack and get larger and larger.

This can make debugging Tram-One internals harder, and could have unintended side-effects when it comes to state-cleanup (from #187). This should only happen in development, so it's not super critical that we fix this, but it should be on our radar.