Allow duplicated rows in relations

[llrs]

Duplicated rows should contain the same information about fuzzy, elements and sets. But can contain different type of relationship, source of the reference, date of annotation or other type of information. All the methods that use the relationship will be affected:

• [x] *_size
• [x] move_to/move_from?
• [x] incidence
• [x] union
• [x] intersection
• [x] complement
• [x] subtract
• [x] nRelations
• [x] add_relations
• [x] group
• [x] remove_relations
• [x] getOBO will work now
• [x] nested
• [x] droplevels (Just in case)
• [x] fuzzification (Although that function need more work)
• [x] tidySet.Annotation (for GO.db)
• [x] Remove duplicated_relations

[llrs]

I close the issue but it might resurface