Fixes mustache rotation

Author: wendelscardua

lib/mustachio/factories.rb

@@ -30,7 +30,7 @@
       # of the upper lip, and the bottom-center of the stache
       # is mapped to the center of the mouth
 
-      rotation = 90.0 - (Math.atan(( face['mouth_center']['y'] - face['nose']['y'] ).to_f / ( face['mouth_center']['x'] - face['nose']['x'] ).to_f ) / Math::PI * 180.0)
+      rotation = -90.0 + (Math.atan(( face['mouth_center']['y'] - face['nose']['y'] ).to_f / ( face['mouth_center']['x'] - face['nose']['x'] ).to_f ) / Math::PI * 180.0)
       desired_height = Math.sqrt(
                                  ( face['nose']['x'] - face['mouth_center']['x'] ).to_f**2 +
                                  ( face['nose']['y'] - face['mouth_center']['y'] ).to_f**2