Bug 1054326: Initial attempt to submit Imagecompare test framework and test cases int...

...o the main branch
I realized what was happening.  Because the new screenshot method happens instantly, it captures the screen while it's still drawing!  so as a temporary fix, I left the time.sleep(2) at the beginning of the screenshot method.  If there is a method that I can use to make sure no visual changes are happening at the moment, I could use that instead.