fixing region parameter on freeze_region

I was having trouble with getting good results from the freeze_region function when I specified a region. Specifying an outer_region gave exactly the expected response, but specifying a region positioned the region at 0,0 regardless of the values of x1 and y1. I get the correct results when I rewrote and tested the function by setting the position last instead of first (lines 38 - 40). Issue here: Zulko#146 (comment)

moviepy/video/fx/freeze_region.py

@@ -35,9 +35,9 @@ def freeze_region(clip, t=0, region=None, outside_region=None, mask=None):
 
         x1, y1, x2, y2 = region
         freeze = (clip.fx(crop, *region)
-                      .set_position((x1,y1))
                       .to_ImageClip(t=t)
-                      .set_duration(clip.duration))
+                      .set_duration(clip.duration)
+                      .set_position((x1,y1)))
         return CompositeVideoClip([clip, freeze])
 
     elif outside_region is not None:
@@ -53,4 +53,4 @@ def freeze_region(clip, t=0, region=None, outside_region=None, mask=None):
         freeze = (clip.to_ImageClip(t=t)
                       .set_duration(clip.duration)
                       .set_mask(mask))
-        return CompositeVideoClip([clip, freeze])
+        return CompositeVideoClip([clip, freeze])