We'll keep on using the master branch for development. The nightlies for Windows and Mac are now using the master branch. Of course, it means that the nightlies will again become quite unstable, so I would refrain advising users on the forum to use them without a lot of precaution. Also note that the file format changed in the nightlies/master branch, it's now 2.07 and so MuseScore 2.0.X will not open these files without a warning and a crash depending on the features used in the score.
Do we do a 2.0.3 release?
"Never says never"... These bugfix releases have really been time consuming for developers... As we want 2.1 ready as soon as possible, I believe it would be better to focus on 2.1. Of course, if we find anything big and easy to fix, a 2.0.3 version is not out of the question but it wouldn't be as large as 2.0.1 or 2.0.2.