fix null/non-null equality, bad bug

fixes #74

Author: emmanueltouzery

src/Comparison.ts

@@ -82,7 +82,7 @@ export function stringHashCode(str: string): number {
  * if possible, degrades to === if not available, and is also null-safe.
  */
 export function areEqual(obj: any|null, obj2: any|null): boolean {
-    if (obj === null != obj2 === null) {
+    if ((obj === null) != (obj2 === null)) {
         return false;
     }
     if (obj === null || obj2 === null) {

tests/Option.ts

@@ -17,6 +17,8 @@ describe("option comparison", () => {
        assert.ok(Option.of(5).equals(Option.of(5))))
     it("should mark different options as not equal", () =>
        assert.ok(!Option.of(5).equals(Option.of(6))))
+    it("should mark different options as not equal", () =>
+       assert.ok(!Option.of<any>(Vector.of(12, 2674)).equals(Option.of<any>(null))))
     it("should mark none as equals to none", () =>
        assert.ok(Option.none<string>().equals(Option.none<string>())));
     it("should mark none and some as not equal", () =>