Replace source-controlled tinyxml with download script

Added get3rdparty.bat and removed 3rdparty/tinyxml directory.
The script will download a tinyxml zip file from SourceForge
and un-zip it into the 3rdparty directory.
Removed *.vcproj from vcproj/vc10

Visual Studio 2010 project files are *.vcxproj. The .vcproj files
were left over from the upgrade.
Removed 3rdparty/UnitTest++ directory

UnitTest++ is now downloaded and unzipped by get3rdparty.bat