Modify Lua module loader to trace each file as it's executed

If we can prepend every Lua file Torchbear runs with
```
log.trace("running: " .. debug.getinfo(1, 'S').source)
```
Then it'd be much easier to debug.

Since bridge.lua already sends off into the app, I think we'd have to modify the package searcher to basically do standard `require()`, but just add that one liner ahead of the module to run.

Possible?

---
or add `need`, `use`, or `run` instead of require