Adds image data to the default cube fixture and enlarge tests (#3840)

* refactored enlarge.

* Added setinputcube call.

* Removed return from setinputcube.

* Removed print.

* Added fixture for adding image data to a cube.

* Need to add changed files to a different machine.

* Changed SetOutputCube call so we can pass in the ui object.

* Added enlarge tests.

* Removed Makefile tests.

* Added CubeAttribute.

* Fixed typo.

* Refactored opening input cube