Replace or supplement resources_dir by/with resources_paths

[PSteinhaus]

We currently have the option to add more paths to search resources in, but AFAIK we lack the ability to actually show them, apart from calling print_all that is.

Therefore why don't we add something like resources_paths that does just that? IMO it might even be a useful replacement for resources_dir, because why would you ever want to look at the same value you set inside of the config again (apart from debugging internal ggez bugs * cough *) this way?
What one is really interested in are the paths where resources are actually searched under, right? (Ok I guess a similar argument could be made here that you've set them yourself, but still: these are a bit less trivial than just echoing that one config value back to you)

In case you'd actually find this useful let us know! (Of course also feel free to criticize the idea ;) )

[a1phyr]

Actually this would be useful for ggez-assets_manager to be able to list additional paths with the FileSystem only, and not provide another method and require to duplicate this information.