- graph plotting via extension system

… some physics and preliminary results also

… (to be consistent with `mulliken`)

…axis orientations

- returns the set of possible transformations between sub or supergraphs, exploring all possible paths through the conjugacy classes and sub/supergraph structure

… probably be an issue

…loit subgroup relations

- this does quite an involved set of checks to carefully understand how a given irrep may be subduced into irreps of a subgroup; the tricky thing is to keep in mind that the subduction might involve a basis change (of the k-point, the little group operations; it may even impact the irreps of nonsymmorphic cases)

- eventually, much of this should be factored out into separate methods since it is not specific to Weyl points

- also adds some graph construction to visualize the relationships between base

- bad copy-paste typo in `build/setup_2d_littlegroup_irreps_nonzymmorph.jl` that meant we had never actually recorded the Y-irreps of plane group 7 (p2mg)
- update the irrep data for plane groups to fix this
- update our calculated `BandRepSet`s for plane group 7 as well
- fortunately, this omission does not change what is inferred about the possible symmetry-detectable topology in plane group 7: e.g., there are still no fragile phases detectable after the correction.

…r consistency with other plane group irreps

…before free variables

- this is in order to parse formats from Bilbao more correctly in general

…` and `subductionsd(-tr).jld2`

- this fixes issues for space groups 143, 147, 149, 150, 156, 157, 162, 164, 168, 174, 175, 177, 183, 187, 189, 191 where the parsed `KVec` was previously wrong (because Bilbao included a multiplication `*` sign in their **k**-vector listings for these groups, which we didn't parse correctly; we do now, cf. 03a9e315304c44085d508f4ddbc06913d4cd3954).

- additionally, it seems that Bilbao has been updated to include several (for some ~151 groups in TR-invariant cases, e.g.,) additional monodromy-related points in their k-connectivity listings of nonsymmorphic groups; we now included these as well.

…urn info about _how_ they are compatible

- also make a bit more general

…ractions in free part

…rsect`

- also various improvements to generality and type-stability; can now be used whole-sale.

…lections of `AbstractIrrep`s

- also improve associated `show` methods

…ify "adding" time-reversal to a dict of `LGIrrep`s

- export `realify!` as well

…d `AbstractVec`s

…s the computes the set of `LGIrrep`s associated with a point in the star of an input set of `LGIrrep`s

- TODO: tests and docstring; only used in BandGraphs atm

…ovements, and new functionality

- fixes a few real bugs from merge, but mainly avoids a set of pointless differences with master branch

…or` from BandGraphs

- speeds up `solve_subset_sum_variant` dramatically for most cases
- also improve how `Model` is instantiated, to save time on this

…ix two issues with BCS band-paths data

- we now load a list of corrections into the tabulated band-paths data
  (corrections stored in `src/subduction-table-corrections.jl`)

- this commits a large number of updates to the BandGraphs code; many aspects have received corrections, very aggressive performance optimizations (e.g., work-arrays), as well as algorithmic improvements (e.g., checks of articulation point), and many changes to the types
- we also now do a much more general job of splitting degeneracies: in particular, we now allow splitting of degeneracies connected to non-nondegenerate nonmaximal irreps; this required multiset permutations.
- the main point of entry at the moment is in `test/scan-separable-irreps.jl`

…ger needed (#59 has been resolved earlier)