allow option for Make Reactor Mode to avoid cd-ing to toplevel

With MNG-2576 the Make Reactor Mode was invented.
However stated in MNG-3377 there is some disappointment about the solution:
<cite>
... ask what's first maven users typical experience:
You do "mvn install" on some module. Then maven starts working and says "oh, I need <foo> to be installed first".
Then you "cd" around to <foo> and do "mvn install" and maven says "oh, I need <bar> to be installed first".
In the end the users says "hey, why do I have to do all this, if maven has all information available in my POMs?
...
However this can already be done with "--also-make-dependents" but maybe not in a way
that users typically work.
</cite>

So what I suggest is that if "-amd" is specified without "-pl" then this is the same
as cd ../../.... (or whatever up to root) and then doing
mvn -amd -pl foo/bar/.... (all the way back)
You might also prefer adding a new option for that.