Find better alternative for manually enabling/disabling modules

[bertfrees]

The reason for disabling modules is because in general always re-building all modules is overkill and takes a long time. It would be better to re-build everything that may potentially fail because of backward-incompatible changes in dependencies (or mistakes in semantic versioning). However to build something that has no changed dependencies is unnecessary.

So two things are needed for this:

• [x] Incremental build system that automatically detects when something needs to be re-build.
• [x] Faster running of tests

EDIT: A second reason is that we don't want to release modules that haven't changed.

• [x] Solve this by enhancing the release script.