[sugar etiona] Develop activity only shows activities you've downloaded

The first time you open Develop, there are no activities to choose from, and it's unclear how you get it to do anything at all. It would be better if the preinstalled Activities could be opened to give a more encouraging first approach to Develop.

This could be achieved by cp -r /usr/share/sugar/activities though it occupies 400MB. Other solutions, like symlinking, do not work as you cannot save or run a modified activity. A cheaper option would be to use cp -rs to make symlinks to the files and to modify Develop to make it delete and create instead of writing to the source file.

Or just make everything under /usr/share/sugar/activities owned by user trisquel and symlink ~/Activities to there.