fix legend titles, units, total plots

[orichters]

all images have left: old and right: new

• if all data is from the same model, state that in the legend title and shorten the line description.

• if all data is from the same scenario, state that in the legend title and shorten the line description.

• fix that the correct plot where to add the total is not found by specifying the identifier in showAreaAndBarPlots and passing that the scenario column before plotting the total. Fixes mipArea does not find correct plots for totals #64

• fix strange coloring where multiple models had the same color

• add some simple tests for mipArea and mipLineHistorical
• fix size warning ggplot2 was complaining about and replacing by linewidth
• further harmonize parantheses around units
• add color.dim.name to further functions so it can be specified from outside (particularly piamInterfaces::plotIntercomparison. Will fix droplevels in mipArea etc. drop deletedinfo attribute #67

Here you can find further files old vs. new so you can see I have not broken compareScenarios2 etc: /p/tmp/oliverr/output/

[orichters]

The new tests complain:

`aes_()` was deprecated in ggplot2 3.0.0.
ℹ Please use tidy evaluation idioms with `aes()`
───────────────────────────────────────────
`aes_string()` was deprecated in ggplot2 3.0.0.
ℹ Please use tidy evaluation ideoms with `aes()`

But I think we can live with that at the moment until somebody knows how to fix that…

[pfuehrlich-pik]

Uh, is that an Elvis operator for R? I was always wondering how to do that!

[orichters]

I never heard of "Elvis operator", but this does not seem to be such an implementation, because it does not return attr(x$identifier, "deletedinfo") if it evaluates to TRUE, but if it does not evaluate to NULL.

[orichters]

So it seems this is a Null coalescing operator.

[orichters]

c(intersect(a, TRUE), b)[[1]] is Elvis, I guess :)

No, it is isn't, because Elvis operator means b is not even evaluated. So forget all that :)