FeynRules/Arts/Calc example

[og113]

The bones of this are in PR #5, but this should be well explained and tested by someone else.

[og113]

In fact, I think it would be reasonable to include the Feyn... files for all the examples which are tested.

[og113]

I changed my mind about including FeynCalc stuff for all models, as I currently have to use a few hacks to get the different Feyn... packages to talk to each other properly, especially for vector fields. For now, I am happy with the Yukawa model example, though it would still be good if someone else could test it.

[og113]

@pschicho have you tried running the Yukawa FeynRules/Arts/Calc example I have put on the repo? I just want to check that somebody else can run it successfully before closing this Issue.