Added Apoorv Upreti's GSoC2013 work: visual test suite.

See visualtest/README.txt for details.

visualtest/launch_harness.cmd

@@ -0,0 +1,2 @@
+start /wait testharness.exe --config testsprite2_crashtest.config > testrun.log 2>&1
+if %ERRORLEVEL% NEQ 0 echo TEST RUN FAILED (see testrun.log)