Fix bfGetPlane tile input check

See https://www.openmicroscopy.org/community/viewtopic.php?f=13&p=13976

`bfGetPlane` could be failing when loading tiles from image with asymmetric XY dimensions due to an improper imput check. This PR should:
- fix `bfGetPlane` to allow `bfGetPlane(r, 1, x, sizeX+1, 1, 1)` to return a value for an image where `sizeY > sizeX`
- add unit tests to cover this test case in the future