Check matching

[felixhekhorn]

these are (mostly) some plotting scripts to check matching away from threshold is working in eko - in especially redo fig. 6 from the eko paper for PDFs.

While doing this I did indeed find a bug: d671cc0 introduced with #172 in develop (not in v0.10 which I was using for the "quick" plot @alecandido - I have to redo my current version of the plots). I still have to fix all the tests.

[alecandido]

@felixhekhorn instead of manually squaring all of those instances, wouldn't just be easier to add a squared properties to MatchingScales?

[felixhekhorn]

@felixhekhorn instead of manually squaring all of those instances, wouldn't just be easier to add a squared properties to MatchingScales?

This had the least impact on the eko module (since the linear already got computed). We can reconsider this in #181. I would try to close this asap to not block an eko release.

The base branch was changed.

[alecandido]

I liked more to have the type, but maybe we should solve later on in a more involved way: we can consider to have inheritance from a couple of markers like EnergyScale and SquaredEnergyScale (unless we can parametrize type with numbers, then we can use EnergyScale[1] and EnergyScale[2]) in order to make our code safer and more explicit.

I'd really like to clean up consistently the usage of linear and squared scales. But we will do in a separate PR.