nodetypes: added isVisible; moved hide/show to DagNode
nodetypes: added isVisible; moved hide/show to DagNode

juggernate/pymel,shrtcww/pymel,AtonLerin/pymel,assumptionsoup/pymel,assumptionsoup/pymel,david-lassonde-adsk/pymel,leonsooi/pymel,AtonLerin/pymel,david-lassonde-adsk/pymel,juggernate/pymel,leonsooi/pymel,shrtcww/pymel