Fixed compare issue. Also updated unit test to reflect improved similar image performance

engine/src/main/scala/com/sothr/imagetools/engine/image/SimilarImages.scala

@@ -34,7 +34,6 @@ class SimilarImages(var similarImages: Set[Image]) extends Logging {
 
   def ordering() = {
     1 * similarImages.size
-    similarImages.groupBy(img => img.getImagePath)
   }
 
 }

engine/src/test/scala/com/sothr/imagetools/engine/EngineTest.scala

@@ -19,7 +19,7 @@ class EngineTest extends BaseTest {
     assertResult(1) {
       similarImages.length
     }
-    assertResult(2) {
+    assertResult(3) {
       similarImages(0).similarImages.size
     }
   }
@@ -37,7 +37,7 @@ class EngineTest extends BaseTest {
     assertResult(1) {
       similarImages.length
     }
-    assertResult(2) {
+    assertResult(3) {
       similarImages(0).similarImages.size
     }
   }