[sugar] versions of bundles

[Tomeu Vizoso]

Hi,

from Update.2, we'll be able to manage several versions of the same
bundle in Sugar.

Until know, we only allowed having one bundle, and the user could only
upgrade to later versions.

Changes needed:

- anywhere the shell displays a launchable bundle in the UI, launch
that specific version (done, will send patch next),

- the version of the bundle that produced a journal entry needs to be
stored in the journal,

- the presence service needs to send the bundle version of the shared activity.

Right now, whenever we need to refer to a specific bundle but we lack
a version number, we are choosing the latest installed version of that
bundle. We should aim to always know which version we should
launch/display.

Tomeu