Add more non-printing Unicode characters

[MrAlexWeber]

Great project!
I found a list of more non-printing characters from this Unicode document: http://www.unicode.org/charts/PDF/U2000.pdf
Some of these characters seem like they could be included in the list of 'unsafe' characters that's checked, e.g.:
RLM, LRM, Various spaces (\u2000 - \u2000a), Spaces, Dashes, Quotation marks, Format characters \u2028 - \u202f and \u2060, Invisible operators, Format characters, and the Deprecated section.
Best regards, Alex

[DavidJacobson]

Thanks!
I'm going to go through these, great find. Leaving this open until I'm able to go through all of them.