Change directory structure?

[seanchen1991]

Basecoin's current directory structure uses a pattern of <name>.rs alongside a /<name> directory. While this works, we could move all of the <name>.rs files into the /<name> directories and change the filenames to mod.rs. This shouldn't break any existing paths or imports, and I think it makes for a cleaner and easier-to-parse directory structure.

What do folks think about this proposed change? 🙂