Initial minor updates to fix a bug in unit test code, and allow specification of non-default test image in BaseApiTester.

Hi Charles,

I wanted to thank you for putting this up on here.  I was starting down the same path when I stumbled on your project and saw that you've already bundled things up nicely.

This initial pull request contains a couple of minor updates to get a failing test going, and to allow specification of an alternate test image on the BaseApiTester commandline...  but more importantly it allows me to say hello.

Once I get my bearings I may be able to help with one or more of the larger tasks you'd identified in the readme.  In the meantime, I'll send pull requests from time to time with minor updates that accumulate as I'm working my way through.

Thanks again,

Tyler