Revert removal of compare nesting

Since we want the user to be able to pass a negative comparison function, the extra layer of wrapping is now needed

spec/core/matchers/toBeNaNSpec.js

@@ -1,35 +1,35 @@
 describe("toBeNaN", function() {
   it("passes for NaN with a custom .not fail", function() {
-    var matcherComparator = j$.matchers.toBeNaN(),
+    var matcher = j$.matchers.toBeNaN(),
       result;
 
-    result = matcherComparator(Number.NaN);
+    result = matcher.compare(Number.NaN);
     expect(result.pass).toBe(true);
     expect(result.message).toEqual("Expected actual not to be NaN.");
   });
 
   it("fails for anything not a NaN", function() {
-    var matcherComparator = j$.matchers.toBeNaN();
+    var matcher = j$.matchers.toBeNaN();
 
-    result = matcherComparator(1);
+    result = matcher.compare(1);
     expect(result.pass).toBe(false);
 
-    result = matcherComparator(null);
+    result = matcher.compare(null);
     expect(result.pass).toBe(false);
 
-    result = matcherComparator(void 0);
+    result = matcher.compare(void 0);
     expect(result.pass).toBe(false);
 
-    result = matcherComparator('');
+    result = matcher.compare('');
     expect(result.pass).toBe(false);
 
-    result = matcherComparator(Number.POSITIVE_INFINITY);
+    result = matcher.compare(Number.POSITIVE_INFINITY);
     expect(result.pass).toBe(false);
   });
 
   it("has a custom message on failure", function() {
-    var matcherComparator = j$.matchers.toBeNaN(),
-      result = matcherComparator(0);
+    var matcher = j$.matchers.toBeNaN(),
+      result = matcher.compare(0);
 
     expect(result.message).toEqual("Expected 0 to be NaN.");
   });