As we'll be creating a deeper hierarchy of modules subordinate to
layout, we need to keep the module full paths short to prevent tem from
growing uncontrollably.
The geometry graph is where the layout's dots, segs, and bends are
stored. The connectivity graph is where information about connected
components and relations between tem (e.g. which ones are connected with
bands) and information common to all band primitives are stored.
This removes dependency on the Slab library. We may go back to it
sometime in the future if we decide to phase out usage of Petgraph's
`StableDiGraph`.
I've temporarily removed collision/infringement detection in
`.move_dot()` because it was a lot of effort to get it right. We'll deal
with this later.
There's a panic due to mesh edges not being generated properly from
loose bends. But this commit is already very large, so I'm going to fix
this in the next one.
There's also some nomenclature changes.
By "layer" we should be referring to the PCB layers. A "rail" shall be
one in a spatial sequence of parallel and topologically linked tracks,
which together shall be called a "railing".
It will be possible for the mesh to contain additional vertices that
aren't part of the Delaunay triangulation. `Mesh` is now a wrapper over
`Triangulation` that implements the same traits, and will be later
adding its own vertices in addition to the ones from triangulation.
`Dot` becomes `FixedDot` and `LooseDot`.
`Seg` becomes `FixedSeg`, `HalfLooseSeg`, and `FullyLooseSeg`.
`Bend` becomes `FixedBend` and `LooseBend`.
The fixed variants differ from the loose variants by being unchangeable
for the router (though probably will be pushable in some cases, but
that's for later). So typically tey're going to be the initial
conditions.
For now only the fixed variants are used even if actually loose, to
split this change into several commits.
I wanted to name it `String` (as in bowstring), but it's taken in Rust,
and `Bowstring` is longer than just `Bow`, and the thing in question is
very much bow-shaped, so I went with `Bow`.