#13 TinyXML namespace for 2.3.1

[Russ Gibson]

I added support for a TinyXML namespace.

To use, define TIXML_NAMESPACE before including
tinyxml.h and use lib's built with TIXML_NAMESPACE
defined. All classes will have TiXml removed from
their names, and be within the TinyXML namespace.

Although the attached file contains VS.NET 2003
projects, the code changes shouldn't have any problems
with VS6 or VS.NET (famous last words). I have neither
installed anymore, so I haven't been able to try them.

All I did was freshen the zip, and then add the VS.NET
2003 projects and "Namespace_Patch.txt" to the original
2.3.1 ZIP.

[Russ Gibson]

2.3.1 Namespace Patch