Filename mismatches type name

[Mafii]

I was looking at the character normalization/cleanup when I noticed that the file for BillTextFormatter is named BillTextForamtter.cs.

Nothing major obviously, but I thought you'd be interested to fix it anyways. The library works great, thanks so much for your work.
Feel free to close without fixing, I wouldn't mind.

[manuelbl]

Thanks for pointing this out. I'll happily fix it in the next release.