title: OCMock does not return stubbed value in a new instance
body: <p>I have the below class written</p>
  
  <pre><code>@implementation B
  
  - (NSString *)returnMock{
      return @"BBB";
  }
  
  @end
  </code></pre>
  
  <p>And I have the below test written:</p>
  
  <pre><code>- (void)testB {
      id mockB = [OCMockObject mockForClass:[B class]];
      [[[mockB stub] andReturn:@"mock"] returnMock];
  
      //This check is a pass
      XCTAssertEqualObjects(@"mock", [mockB returnMock]);
  
      B *b = [[B alloc] init];
      //This check is a fail
      XCTAssertEqualObjects(@"mock", [b returnMock]);
  }
  </code></pre>
  
  <p>As I understand that, if a mock is created for a class and then for any new instance of it will refer to the mocked class.</p>
  
  <p>If this is not true, can anyone help me in making the second assert to pass after a new instance is created.</p>
  
  <p>Thanks</p>