Allow dashed names

[AndreTheHunter]

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[camsaul]

@AndreTheHunter this looks good, but it would be great to document this somewhere. I think a new section after this one https://github.com/metabase/toucan/blob/master/docs/setup.md#configuring-quoting-style is the best place to put it

[camsaul]

I'll go ahead and merge this and clean up the last couple things.

[camsaul]

Upon some reflection I ended up renaming this to from allow-dashed-names to automatically-convert-dashes-and-underscores (and defaulting to false) since the latter name much more clearly explains what exactly it does. See PR #29