Overview alternative

Now includes the changes as discussed in our meeting on monday and in issue #495 (closed).

Also I added improved handling of margins: there is a new fixedMargins flag, which when set instructs the plots to compute the margins automatically once on startup, after which they are not recomputed until the data changes. This together with some padding make for a nice behaviour even on scrolling and zooming. Only if the user scrolls super much, the labels will start to overlap with titles. But I think this is acceptable considering the benefits.

Things you should note and check:

• I put the encyclopedia button inside the material card as a text-variant with blue color, as discussed. The api button is at the bottom right of the left panel with blue color, but with the contained-variant. We were discussing to use the text-variant also there, but to me it looked very weird.. Also the contained-variant against the gray background is consistent with the buttons on the search page. Change as you see fit.
• The legend is now at top left, with a slightly transparent background. Change as you see fit.
• I picked the ViewList icon for the links to the data in the Archive. Change as you see fit.