Close button sends client to the tray, statically linked Qt for OSX.
See the Changelog for list of features and fixes currently only available in the nightly builds.
Smaller release this time around, this is mainly to address a crash bug that affects certain shared folders. Those experiencing the bug will find their client crashing a short while after starting it. I figured I might as well get it out there for whomever really needs it. Additionally:
Links are on the download page.