Fix API level sensitivity

## Rationale:

The use of the version string 4.+ make the player samples sensitive to API level changes.  Using a version of the form 4.2+ will enable sample apps to keep working in the face of API level changes.

Also, this commit upgrades the OnceUx plugin to work with the new OnceUx Android Library, an API level change.

## Changed files:

BasicOnceUxSampleApp/src/main/java/com/brightcove/player/samples/onceux/basic/MainActivity.java
* Apply changes to support the renamed and refactored (moved) OnceUxComponent (previously OnceUxPlugin).  These changes bring OnceUx in compliance with conventions with other plugins.

release-notes.txt
* Describe this change.