closes #477

This is a big refactor that preserves the original form of the user input into the compiler step (instead of using the formatted version). This allows multiple places in the compilation to check that the user input was unquoted, and if so, don't count it as reserved (among other things, like underscores).

I'm sure I missed some spot where quoting/unquoting is going to result in weirdness -- there's not enough comprehensive tests that exercise quotation to have confidence. But that's okay, this is kind of edge case in that it's mostly useful SQL table and Class shapes. In those instances, the key itself is output to the render, and label is something else. In all other cases, you'd probably just relabel the key instead of using quotes everywhere to try to use a reserved keyword.