Strings::normalize should remove C1 control codes as well

Strings::normalize should remove C1 control codes (U+0080 to U+009F) as well. This would however be a BC break because currently Strings::normalize works for non-utf8 strings as well.

This would also make Strings::normalize behavior closer to what Http\RequestFactory::NONCHARS is used for.

http://en.wikipedia.org/wiki/Unicode_control_characters
http://en.wikipedia.org/wiki/C0_and_C1_control_codes