Add a single-line comment.

[drwhut]

Having multi-line comments will be difficult to work with when it comes to GUI editors storing their metadata.

Maybe have anything after a > be a comment on that line?

[drwhut]

Will probably also remove multi-line comments as well. Having both will be confusing to work with, and the language is designed to be edited with a GUI, so users won't necessarily care about commenting the file directly.