Added unit test for #271
Also check unit test bundle for local file
- this is necessary because for unit tests any resources are in the UnitTest.octest bundle and not the mainBundle.
- this is done in the else of if (path) to minimize impact on performance
fixed textAttachment's displaySize is set to _size when element has a style even if height or width attributes are not available, causing height or width of displaySize set to 0