Encoding parameters: upper/lower case, normalization

[ChristianGruen]

The serializer spec says…

Serializer are required to support values of UTF-8 and UTF-16

…whereas the XQFO spec mentions utf-8 as default value for fn:serialize. Similarly, only the UTF lower-case variants are listed for fn:unparsed-text, and there may be other places.

I think we should mention the upper-case variants everywhere, and add notes that upper/case is ignored when processing the encoding string.