Release branch

Dear roaring IOTlers,

we've finally merged all remaining PRs that were missing for our upcoming release and are now in final testing phase. Therefore, I created a release branch [1] as well as a tag for the first release candidate [2]. Everybody is invited to help testing and finding potential last bugs, before we can finally publish the 2015.09 release this week.

Cheers, Oleg

[1] [2]