A dirty solution to #891

Currently we have no good solution to handle embedded bitmap fonts (#891), so we should avoid using them, until a final patch is available. 
On the contrary, it is much easier to run single tests with nose.

```bash
# Run test class:
$ nosetests -v Tests/test_image_transpose.py:TestImageTranspose
# Run individual test:
$ nosetests -v Tests/test_image_transpose.py:TestImageTranspose.test_rotate_270
```