Fix web site encoding problems

The encoding.html page was generated incorectly, revamp the input
xml.html and convert the full XSLT chain to use and serve it as
UTF-8
* doc/*: fix xml.html, update all stylesheets and regenerate
diff --git a/doc/APIchunk15.html b/doc/APIchunk15.html
index 8bb4437..d18be95 100644
--- a/doc/APIchunk15.html
+++ b/doc/APIchunk15.html
@@ -1,6 +1,6 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /><link rel="SHORTCUT ICON" href="/favicon.ico" /><style type="text/css">
+<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="SHORTCUT ICON" href="/favicon.ico" /><style type="text/css">
 TD {font-family: Verdana,Arial,Helvetica}
 BODY {font-family: Verdana,Arial,Helvetica; margin-top: 2em; margin-left: 0em; margin-right: 0em}
 H1 {font-family: Verdana,Arial,Helvetica}