UTF-8 as default for file sources

XML.read() uses the system default encoding (ignoring what the file itself says).

The correct thing would be to look for a charset attribute in the XML header, defaulting to any BOM-specified encoding if it is not there, and lastly default to UTF-8 if there is no BOM.

This quick fix still ignores what the file says, but defaults straight to UTF-8 and is at least slightly less likely to cause problems.