Drop-in replacement for v0.1.3.

- gplot() and svgplot() now draw links with different line thickness to represent cable type (after assign_cables() is called)
- improve number formatting inside infobox of gplot() and svgplot()
- switch SCIP modelling from Pyomo to PySCIPOpt, enabling the launching of concurrent solvers for the same problem (competitive mode)
- refactor MILP code for reducing code duplication and improving consistency between model descriptions for the different APIs
- add information on how to install missing solvers when a requested solver is not available
- bump dependency NetworkX version to 3.6 (resolves pickling issues with nx.PlanarEmbedding)
- update the documentation to reflect the changes involving solver SCIP and plotting functions
- fix the assignment of graph attributes 'creator' (all solvers) and 'runtime' (scip)