A state that encapsulates a set of {#requirements} with an {Array} of possibilities
Removes a possibility from `self` @return [PossibilityState] a state with a single possibility,
the possibility that was removed from %x`self`
# File rubygems/resolver/molinillo/lib/molinillo/state.rb, line 35 def pop_possibility_state PossibilityState.new( name, requirements.dup, activated.dup, requirement, [possibilities.pop], depth + 1, conflicts.dup ) end