cmake build support for VR demo (WIN32 only)

update to latest OpenVR 1.05 SDK from https://github.com/ValveSoftware/openvr
add keyboard support to tune default camera VR position
VR revert to double 'distorted' views on Desktop, since the single view isn't showing full scene

examples/ThirdPartyLibs/openvr/samples/shared/compat.h

@@ -0,0 +1,27 @@
+#ifndef OPENVR_SAMPLES_SHARED_COMPAT_H_
+#define OPENVR_SAMPLES_SHARED_COMPAT_H_
+
+#include <cstdio>
+#include <cstring>
+#include <cassert>
+
+// Handle non standard code.
+#ifndef _WIN32
+
+#include <cstdbool>
+#include <unistd.h>
+
+#define sprintf_s   snprintf
+#define vsprintf_s  sprintf
+#define _stricmp    strcmp
+#define stricmp     strcmp
+#define strcpy_s(dst, n, src)   int(strncpy(dst, src, n) != nullptr)
+#define fopen_s(fd, path, mode) int((*fd = fopen(path, mode)) != nullptr)
+#define _vsnprintf_s(buffer, size, fmt, ap)  vsnprintf(buffer, size, fmt, ap)
+#define OutputDebugStringA(x) fprintf(stderr, "%s\n", x)
+
+typedef int errno_t;
+
+#endif  // _WIN32
+
+#endif  // OPENVR_SAMPLES_SHARED_COMPAT_H_