Clarified what is treated as an acronym.

Happy to add an example, just wasn't sure how big you wanted that readme to get.

Would you say this is the most appropriate method of ensuring an arbitrary string will be transformed to title case? 

"HUMANIZER".Humanize(LetterCasing.LowerCase).Humanize(LetterCasing.Title) => "Humanizer"

This does seem a bit clunky to me, at least from the perspective of someone working with data that's already mostly human readable (as opposed to acronyms and techy things). I wonder if you think some sort of global switch to ignore all acronyms would be appropriate?