Added midroll, plus pause and resume tests.

BasicIMASampleApp/src/instrumentTest/java/com/brightcove/player/samples/ima/basic/MainActivityTest.java

  * Modified testPlay() to test midrolls.

  * Added testAdPauseResume() and testPlaybackPauseResume().

BasicIMASampleApp/src/main/java/com/brightcove/player/samples/ima/basic/MainActivity.java

  * Modified onCreate() to remove the HLS_URL field from the catalog
    request, so that midrolls can be tested.  Midrolls don't work with
    HLS due to seeking bugs in Android.

  * Modified setupCuePoints() to set the midroll at 10 seconds instead
    of 10 milliseconds.

BasicIMAWidevineSampleApp/src/main/java/com/brightcove/player/samples/imawidevine/basic/MainActivity.java

  * Modified setupCuePoints() to set the midroll at 10 seconds instead
    of 10 milliseconds.
Responses to feedback.

BasicIMASampleApp/src/main/java/com/brightcove/player/samples/ima/basic/MainActivity.java

  * Added comment to explain catalog API request.

  * Modified midroll CuePoint to use DateUtils to make it more obvious
    that the position is in milliseconds.
More pull request feedback.
Merge pull request #6 from BrightcoveOS/midrollPlusPauseAndResumeTests

Added midroll, plus pause and resume tests.