Feature: std.experimental.logger 

dash.utility.output now implements the std.experimental.logger standard, meaning that we'll be ready to start using it as soon as it's merged into phobos. This also gives us the added benefit of the fact that all logging functions now come with an `f` variant, which behaves like `printf`. The only downside is that someone (probably me) will have to go through and change all calls to `logInfo` to `info`, `logError` to `error`, etc., which will be a lot of busy work. I will go ahead and do that though, if you guys think it's something you'd like to see.