pyexiv2.xmp.register_namespace() requires URI ending with /

[Michal Čihař]

pyexiv2.xmp.register_namespace() requires the URI to end with "/"
characters. I believe that this is unreasonable requirement. What the
XMP specification says about the subject is:

“A namespace URI used in XMP should end in a character that is not
allowed in an XML NCName (the local name). Recommended characters are
the slash ("/", U+002F) or the number sign ("#", U+0023). This can
improve compatibility with applications that catenate the namespace URI
and local name, avoiding potential collisions.”

Please allow at least "#" as trailing character in namespace URIs.