(case involves operation of private shooting range in close proximity to subdivision and elementary school; plaintiffs claim that range constitutes public and private nuisance, was an attractive nuisance, violated the Montana constitution and that court had authority to close range because it was a "clear and provable safety hazard"; public nuisance claim improperly dismissed by trial court; trial court improperly dismissed private nuisance claims; trial court improperly dismissed trespass claims and attractive nuisance claim; constitutional issue need not be decided).