SOme ground work to support Windows for benchmark farm

Mainly straightforward changes, the only tricky part: detect number of CPU
sockets. Didn't figure out yet how to do this on Windows.

benchmark/farm.py

@@ -169,8 +169,8 @@ def downloadLatestBlender(directory):
     """
     Download latets Blender from buildbot to given directory.
     """
-    # TODO(sergey): This we need to change to currently running configuration.
-    latest_blender_url = buildbot.buildbotGetLatetsVersion("Linux", "64bit")
+    platform = sys.platform
+    latest_blender_url = buildbot.buildbotGetLatetsVersion(platform, "64bit")
     if not latest_blender_url:
         logger.ERROR("Unable to figure out latest Blender version")
         return
@@ -203,6 +203,8 @@ def findBlenderInDirectory(directory):
     platform = sys.platform
     if platform == 'linux':
         return os.path.join(blender_dir, "blender")
+    elif platform == "win32":
+        return os.path.join(blender_dir, "blender.exe")
     else:
         raise Exception("Need to support your OS!")