message: Fix `-Wreorder -Wimplicit-fallthrough` warnings
diff: #include "writer_xml.h"
  XmlWriter::XmlWriter(std::ostream& filestream) :
  - indent(0),
  stream(filestream),
  + indent(0),
  at_bol(true)
  {
  stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
  @@ -77,6 +77,7 @@ void XmlWriter::Write<std::string>(const std::string& val) {
  stream.put(c);
  at_bol = true;
  Indent();
  + break;
  case '\r':
  case '\t':
  stream.put(c);
  