Add Visual Studio 2013 bat file. Requires CMake 2.8.11.2 or newer for…

… VS 2013 support.

CreateVisualStudio2013Projects.bat

@@ -0,0 +1,18 @@
+@REM Create OpenJK projects for Visual Studio 2013 using CMake
+@echo off
+for %%X in (cmake.exe) do (set FOUND=%%~$PATH:X)
+if not defined FOUND (
+	echo CMake was not found on your system. Please make sure you have installed CMake
+	echo from http://www.cmake.org/ and cmake.exe is installed to your system's PATH
+	echo environment variable.
+	echo.
+	pause
+	exit /b 1
+) else (
+	echo Found CMake!
+)
+if not exist build\nul (mkdir build)
+pushd build
+cmake -G "Visual Studio 12" -D CMAKE_INSTALL_PREFIX=../install ..
+popd
+pause