Added a README file regarding WinRT support

To note, this file is currently formatted with CRLF line endings, rather than
LF, to allow the file to be viewed with Notepad.

visualtest/include/SDL_visualtest_screenshot.h

@@ -0,0 +1,50 @@
+/* See COPYING.txt for the full license governing this code. */
+/**
+ * \file SDL_visualtest_screenshot.h
+ *
+ * Header for the screenshot API.
+ */
+
+#include "SDL_visualtest_process.h"
+
+#ifndef _SDL_visualtest_screenshot_h
+#define _SDL_visualtest_screenshot_h
+
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Takes a screenshot of each window owned by the process \c pinfo and saves 
+ * it in a file \c prefix-i.png where \c prefix is the full path to the file 
+ * along with a prefix given to each screenshot.
+ *
+ * \return 1 on success, 0 on failure.
+ */
+int SDLVisualTest_ScreenshotProcess(SDL_ProcessInfo* pinfo, char* prefix);
+
+/**
+ * Takes a screenshot of the desktop and saves it into the file with path
+ * \c filename.
+ *
+ * \return 1 on success, 0 on failure.
+ */
+int SDLVisualTest_ScreenshotDesktop(char* filename);
+
+/**
+ * Compare a screenshot taken previously with SUT arguments \c args that is
+ * located in \c test_dir with a verification image that is located in 
+ * \c verify_dir.
+ *
+ * \return -1 on failure, 0 if the images were not equal, 1 if the images are equal
+ *         and 2 if the verification image is not present.
+ */
+int SDLVisualTest_VerifyScreenshots(char* args, char* test_dir, char* verify_dir);
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SDL_visualtest_screenshot_h */