Remove loops from graph visualization and edge count

[albertocottica]

It is not clear that loops have meaning in a social network of comments. Removing them improves the clarity of the graph.

[luca]

commenting to say that when we remove loops we'll have to do so by removing (not considering) the network edges generated by comments of a person on their own content (they are currently included in the network)

[albertocottica]

You could also remove all edges where source == target

[luca]

yep that what I meant but badly explained 😄

[jenkin]

Simple filter in preprocessing, but with edgeryders the improvement in visualization is quite useless (loops are ~11% of total edges): Dataninja@a71f78a

[luca]

@jenkin that's ok, I still think removing the loops should be done: as @albertocottica said in the there's a reason of clarity and meaning for removing them

[jenkin]

Ok, loops removed as discussed here: #34 (comment)

[jenkin]

Done in last PR.