New OnceUx Test Class CompanionAdTestCase.java

##Rationale
Now that Companion Ads have been implemented into the Sample App, It's time for tests.
##Changed Files
**CompanionAdTestCase.java**
* New utility methods
    * *companionCheck* finds the companion ad based on the companion ad frame's resource id
    * *toCompanionAdCheck(int msec)* navigates to the next ad break, then performs *companionCheck*. It returns the results of *companionCheck*.
    * *toEndOfAdBreak* navigates to the end of an ad break, hides the seek controls, and then performs *companionCheck*. It returns the results of *companionCheck*.
* New tests
    * **testCompanionAd** navigates through the video using *toCompanionAdCheck* and *toEndOfAdBreak*. After the start of each ad break, it asserts that the companion ad is present.
    * **testCompanionAdLink** clicks on a companion ad and tests for the presence of the browser url the click is meant to link to
    * **testCompanionAdVanish** navigates through the video using *toCompanionAdCheck* and *toEndOfAdBreak*, checking after the end of each ad break for the presence of a companion ad. It asserts that *toEndOfAdBreak* will return false for each ad break.
Assuming that the waitForExists() method works the same as other timeout methods, I'm not sure you get anything out of this method, that you wouldn't get by adding the waitForExists() directly to the companionCheck() method.