Include neutrals in overlap and uniqueness checks

Some duplication in Particle::Selections were observed in lines using the output of SelectionFromWeightedRelationTable.

NOTE:In case you want to fix this offline (this MR will only fix it likely online), use ParticleContainerMerger to transform the selection to a unique set. Something like:

from Hlt2Conf.algorithms_thor import ParticleContainerMerger
my_particles = ParticleContainerMerger(InputContainers=[get_particles("<myselectionfromweightedrelationtable>")]).OutputContainer

Uniqueness criteria extended to neutrals, including overlap check for combiners. Using neutralPID as calos (CaloHypo) is a more expensive check and not unique to neutral objects.

fyi: @johndan @fevolle @mvesteri