resolve ordering of parent build in reactor

previously, parent always built first. This caused issues with cycles when the parent depended on the child (Which may also be the case with modules and an aggregating root if that occurs).

Now, with the parent last, the "clean:clean" command is causing issues (previously it0065 - until dependency on parent's target directory was removed). A child is using/writing to the parent's target directory, and then clean comes and wipes it out.

• is this acceptable?
• what alternatives are there?

Currently proposed solution:

• parent is not factored into dependency graph to avoid cycles
• parent is forced to come before children if not aggregating
• parent is forced to come last if aggregating (currently aggregating doesn't run children anyway, relying on earlier output)