Should not deploy modules unless all modules in a group build successfully

Continuum should not deploy the modules to a maven repository unless all the modules in a group build successfully. If one module fails, this means that the source code is such a state that the modules do not create a functional artifact portfoilo. Hence, they should not be the basis for other builds.

This should perhaps be a selectable per-group policy: choose "always deploy module" (like today) or "deploy only if all successfull".