Allow range to be bound to application data

[exa04]

Allows for values, as well as lenses to be passed into the Graph, Grid, Meter and Oscilloscope.

This pull request introduces the RangeModifiers trait. The trait allows for the respective views to have their ranges and scalings bound to a lens, or set to a value. It is implemented for:

• [x] Graph
• [x] Grid
• [x] Meter
• [x] Oscilloscope

Also, this PR fixes some annoyances when updating the ranges of certain views.

• The UnitRuler hides values that are out of scope, instead of clamping them
• Graphs whose range gets bound/updated after creation will also update their fill position correctly now.

[!CAUTION] This PR introduces a breaking change for graphs! If you want to fill them from a certain position, you will now have to do so by calling fill_from_max or fill_from on them.

[magnetophon]

Going by the checkboxes, this PR is ready for testing. Is it indeed?

[exa04]

Yes, it is :)

[magnetophon]

Great! I will then!

The FillFrom enum looks like a very handy feature. Is it planned for Meter as well? I am currently "hacking" this in for lamb.

[exa04]

Great idea! I'll base the Meter fill logic on that, too.

[exa04]

Alright, LGTM!