This updates the document to have 4 diagrams, one for each of the
following releases:
1. 0.16.x (current stable release)
2. 0.17 (according to current plans)
3. 0.18 (according to current plans)
4. 0.19 (this more of a proposal than a plan at this point)
The diagrams have also been enhanced to differentiate between packages
and modules (aka JARs) and to distinguish between "api" and "implementation"
dependencies.
Hopefully this makes things much more clear. We can make further changes
as our plans and implementations change.
