New build which includes the 0.3.20 release:
https://copy.com/YL2vVHK7vXza
And I'm happy to say that this seems to solve the memory issue that plagued earlier versions, at least on my system. (It appears to have been related to the 0.3.19 experimental build).
If other users can test this as well and report back. There should be no need to force quit the app the first time any more.