Making Suggested Changes

##Changed Files
LearnMoreCheck.java
* removed **learnMoreLatch**
* removed extraneous imports
* initialized **shouldHaveLearnMore** as false by default in the new **setUp()**, which then calls upon super.setUp.
* renaming **seekControls()** to **toggleSeekControlsVisibility()**
* **learnMoreChecker()** now returns a boolean value depending on the presence of the learn more button (*true* for present, *false* for not present), and takes over the role **learnMoreLatch** used to fill in terms of asserts.
* added assertions for **shouldHaveLearnMore** to each test.
* fixed some syntax
* added comment explaining why Midrolls are assumed to not have the Learn More button.