Condensed Debug representation

[LeopoldArkham]

Pretty printing the parser's result... isn't. To make debugging easier, we should override it so it uses less frivolous newlines and indentations, and shows a more ad-hoc representation of containers.

[LeopoldArkham]

Since this would need to keep track of indentation, we can't just override debug implementations, so you would have to write functions that accept an indent level as an argument, and just call those from the TOMLDocument's debug implementation.