The classloader project dependencies are loaded onto is reused between
modules, so each module was a superset of all modules that preceded it.
Also, the console, execute, and shell mojos didn't pass the classloader
to use into the instantiated GroovyConsole/GroovyShell, so it
accidentally was using the plugin classloader, even when configured to
use PROJECT_ONLY classpath.
Potentially breaking changes
This should be a non-breaking change (except for unusual situations
that were relying on the previous incorrect behavior). However, since
it's a significant change, I'm bumping the version by more than just the