Wrap-up (or objectives)

These are too abstract as an introduction: better to leave them for the conclusion. Maybe after the build system description?

• Share to manage, manage to share
• The distinction between source elements and derived objects should be secondary, hidden at first
• Manage vs control, continuity and asynchrony
• Collective, scalable activities: not only extrapolated from individual tasks
• Builds as nested transactions: needed for Java build system