TST: Add units tests for direct comparison with matlab

[carterbox]

Purpose

Check for consistency between key/some/various MATLAB and Python functions.

Approach

First write a matlab script which generates a random input for a MATLAB function. Then record the inputs and outputs of the function in a v7.3 matlab file (hdf5). Compare the output of the corresponding Python code with the same inputs. Use single precision inputs and outputs to keep files below GitHub file limits.

Pre-Merge Checklists

Submitter

• Write a helpfully descriptive pull request title.
• Organize changes into logically grouped commits with descriptive commit messages.
• Document all new functions.
• Click 'details' on the readthedocs check to view the updated docs.
• Write tests for new functions or explain why they are not needed.
• Address any complaints from pep8speaks.

Reviewer

• Actually read all of the code.
• Run the new code yourself; the included tests should make this easy.
• Write a summary of the changes as you understand them.
• Thank the submitter.