More test cases for the Discovery class (Total coverage: 93.8%).

* testEnableWillCreateAndStartDiscoveryThread()
* testEnablingDiscoveryTwiceThrowsException()
* testCallingDisableWillCallDisableDiscoveryOnThread()
* testCreateDiscoveryThreadReturnsNewInstance()
IntentChat sample application: Remove custom build with 1.0-SNAPSHOT build.