Automatically detect blender version for benchmark script on windows

run.bat

@@ -4,13 +4,24 @@ rem set SCRIPTPATH_SLASH=%~dp0
 rem set SCRIPTPATH=%SCRIPTPATH_SLASH:~0,-1%
 set SCRIPTPATH=
 set BOOTSTRAP_VERSION=0.1
-set BLENDER_VERSION=2.78
+set BLENDER_VERSION=
 
 reg Query "HKLM\Hardware\Description\System\CentralProcessor\0" | find /i "x86" > NUL && set BITNESS=32 || set BITNESS=64
 
 echo Cycles Benchmark Suite bootstrap v%BOOTSTRAP_VERSION%
 echo Detected OS: Windows %BITNESS%bit
 
+for /l %%x in (9, -1, 0) do (
+  for /l %%y in (99, -1, 10) do (
+    if EXIST %SCRIPTPATH%blender\windows%BITNESS%\%%x.%%y (
+      set BLENDER_VERSION=%%x.%%y
+      goto GOT_VERSION
+    )
+  )
+)
+
+:GOT_VERSION
+
 set BLENDER_DIR=%SCRIPTPATH%blender\windows%BITNESS%
 set BLENDER_BIN=%BLENDER_DIR%\blender.exe
 set SCENES_DIR=%SCRIPTPATH%scenes