Make fp.without an alias of fp.difference. [closes #2122]

fp/_mapping.js

@@ -36,6 +36,7 @@ exports.aliasToReal = {
   'unnest': 'flatten',
   'useWith': 'overArgs',
   'whereEq': 'filter',
+  'without': 'difference',
   'zipObj': 'zipObject'
 };
 
@@ -163,7 +164,8 @@ exports.methodSpread = {
   'invokeArgs': 2,
   'invokeArgsMap': 2,
   'partial': 1,
-  'partialRight': 1
+  'partialRight': 1,
+  'without': 1
 };
 
 /** Used to identify methods which mutate arrays or objects. */

test/test-fp.js

@@ -471,7 +471,7 @@
       assert.expect(10);
 
       var array = ['a', 'b', 'c'],
-          other = ['b', 'b', 'd'],
+          other = ['b', 'd', 'b'],
           object = { 'a': 1, 'b': 2, 'c': 2 },
           actual = fp.difference(array)(other);
 
@@ -495,7 +495,7 @@
       actual = fp.uniqBy(_.identity, other);
       assert.deepEqual(actual, ['b', 'd'], 'fp.uniqBy');
 
-      actual = fp.without('b')(array);
+      actual = fp.without(array)(other);
       assert.deepEqual(actual, ['a', 'c'], 'fp.without');
 
       actual = fp.xor(other)(array);