As promised there is now a repository for the latest version of the Java Molecule editor question type for Moodle 2.2.x:
and also for Moodle 2.3.x:
If you don't use git, I have provided instructions to download as a zip archive and install (See README.md). Post a message here if you encounter any problem.
Unfortunately, if I have permission from ahtor Peter Ertl, to include the JME.jar file in a zipped archive of the question, I don't think I can post it to a public git repository.
So you will have to get it separately (instructions to do so are also included in the README.md file) and put it in question/type/jme/jme/
I will create a MOODLE_24_STABLE branch later but I am quite sure the version from the MOODLE_23_STABLE branch can be used with Moodle 2.4.x too.
On the contrary don't try to use the master branch with Moodle 2.5dev, it is not ready and it will not work.
Please report any problem with one of these versions here, as I am commited to maintain this plugin.
Note: The XML import/export is working in these versions. I think it was broken in some earlier versions.