Fixed currently playing file and playlist operations when response is not valid because file is not playing or playlist is empty on the server
Changed release information
[maven-release-plugin] prepare release thedavidbox-client4j-1.2.1
[maven-release-plugin] prepare for next development iteration
Merge branch 'release/v1.2.1' into develop

merge the version back into develop
Rectified build status and coverage status to develop