Various improvements

[luucvanderzee]

• Improved Grid component API (for example, it can automatically determine rows and columns now)
• Added 'rasters' (those gridlines that extend axis ticks)
• Implemented clipping functionality from PR #177

[atepoorthuis]

Nice work! Three comments:

• There was an empty unit test for the updates in the Grid component. Did you mean to add some tests there? I have removed it temporarily so the CI will pass.
• The 'raster' component is a great addition! I'm not sure about its naming though since it deviates a bit from the most commonly used names for these (grid lines, guides) and might also be confusing to those coming from mapping as 'raster' has a specific connotation there. Shall we rename to guides perhaps?
• Can you add a simple integration test for the new raster/guide component? I'd like to make sure we have at least a simple test for each main component to ensure things don't radically break. Might also be nice to add something to the sandbox for future dev (you probably already have something like it created from when you were implementing the feature?).