Normalize line endings in the Reader as the spec requires, which was not
done before:
- CR and CRLF fold to a single line feed (XML 1.0), so every downstream
scan sees line feeds only.
- When the declaration names version 1.1, NEL (U+0085) and LINE SEPARATOR
(U+2028), and a CR followed by NEL, also fold to a line feed; in 1.0
those characters are preserved as data.
The XML 1.1 name-character productions are identical to XML 1.0 Fifth
Edition, which the character classifier already implements, so names need
no change. The 1.1 character range (C0 controls permitted only as
references) is not yet enforced.
Closes#96