* Moved commands into their own folder to reduce `bin.rs`'s size
* Moved all of the VFS-related functionality into its own folder
* Documented a lot of functions, including a few very obscure ones
This solves the problem I was running into with the ScriptPlugin implementation -- if foo/init.lua changes, foo needs to be requested, not 'foo/init.lua' (which would then erroneously create a ModuleScript before this commit)
