Links to LiberTEM issue https://github.com/LiberTEM/LiberTEM/issues/1271
Includes tests in the source tarball so that conda build can run them.
Also fixes a potential bug in array_ufunc:
Specifically when the out= kwarg to the ufunc was (None,) numpy was raising a TypeError. I've added a line which converts the single-entry (None,) to just None and now no problems (with the tests). [Mixed/mutil-array out= or single-array out will still remain as they are.]