[[!comment format=mdwn
 username="joey"
 subject="""comment 3"""
 date="2017-02-02T18:45:01Z"
 content="""
That example with reverting one property overriding another property
is a general problem propellor has with conflicting properties. 
Normally I don't much worry about it, but I agree an accidental mass
upgrade is a good reason to avoid that problem here.

Yes please add a new type alias for String (or an ADT) 
if Package is not appropriate.

I had misunderstood which function the TODO was for..

Nice surprise that tightenTargets works on RevertableProperty at all.
Since it does, you should be able to tighten one side, revert, tighten the
other side, and re-revert. Or, deconstruct the RevertableProperty, 
tighten both sides individually, and reconstruct it.

I've added a Propellor.Property.File.configFileName that 
should be suitable for your purposes, and others..
"""]]
