Fix remaining warnings in sphinx build (see gh-148)
Fix remaining warnings in sphinx build (see gh-148)

rdhyee/PyTables,tp199911/PyTables,mohamed-ali/PyTables,tp199911/PyTables,tp199911/PyTables,dotsdl/PyTables,rdhyee/PyTables,joonro/PyTables,mohamed-ali/PyTables,andreabedini/PyTables,dotsdl/PyTables,tp199911/PyTables,jennolsen84/PyTables,dotsdl/PyTables,gdementen/PyTables,cpcloud/PyTables,jack-pappas/PyTables,rabernat/PyTables,jack-pappas/PyTables,FrancescAlted/PyTables,jack-pappas/PyTables,jack-pappas/PyTables,cpcloud/PyTables,FrancescAlted/PyTables,rabernat/PyTables,mohamed-ali/PyTables,rdhyee/PyTables,jennolsen84/PyTables,rdhyee/PyTables,rabernat/PyTables,PyTables/PyTables,gdementen/PyTables,PyTables/PyTables,mohamed-ali/PyTables,avalentino/PyTables,cpcloud/PyTables,gdementen/PyTables,PyTables/PyTables,avalentino/PyTables,jennolsen84/PyTables,andreabedini/PyTables,joonro/PyTables,cpcloud/PyTables,jack-pappas/PyTables,rabernat/PyTables,andreabedini/PyTables,joonro/PyTables,joonro/PyTables,FrancescAlted/PyTables,dotsdl/PyTables,jennolsen84/PyTables,andreabedini/PyTables,gdementen/PyTables,avalentino/PyTables