Providing dids to specify isget for ids in MultiIDSLoader should accept common idd identifiers

[Didou09]

This (or something as simple) should work (useful for IMASViz):

multi = tf.imas2tofu.MultiIDSLoader(shot=54178, user='imas_public', tokamak='west',
                                                           dids={'bolometer': {'ids': bolometer, 'isget':True},
                                                                      'wall': {'ids': wall, 'isget': True}})

Right now, it seems we have to provide the idd for each ids independently

[Didou09]

Solution already existed but never tested (small bug needed correction):

multi = tf.imas2tofu.MultiIDSLoader(shot=54178, user='imas_public', tokamak='west')
multi.add_ids(bolometer, isget=True)
multi.add_ids(wall, isget=True)

FIxed, in devel, by PR #317