Roadmap to `v0.1` - Githubissues

Things to polish/finish prior to release:

[x] Streamline how boundary conditions are passed to the LevelSetEquation constructor. Example that should work: #35
```
bc = (PeriodicBC(), (NeumannBC(), DirichletBC()))
bc = PeriodicBC()
bc = NeumannBC()
```
Example that should error:
```
bc = ((PeriodicBC(), DirichletBC), ...) # error
```
[x] Decide on what a boundary condition means when indices are out of bounds in more than one dimension #35

[x] General section on package usage, overview, etc @maltezfaria #36
[x] A section on LevelSetTerm
- [x] Pour la courbure on peux se servir de la spirale #37
- [x] Advection term (done in #38)
[x] Time integrators (done in #39)
[x] Boundary conditions
[x] Extensions
- [x] Makie
- [x] MMG #37
[x] Examples
- [x] Zalesak circle (WENO vs. upwind)
- [x] Shape optimisation #37
- [ ] Maybe Eikonal solver using reinitialisation (v0.2.0)
- [ ] Shape optimisation using integral equations for Laplace problem (v0.2.0)

[ ] Remove dead code using Codecov once docs are written and coverage is setup to track docs (v0.2.0)
[x] Clean export
[x] Modify Makie recipe to use contourf to distinguish inside/outiside
[x] Write the _normalize_bc function #35

maltezfaria / LevelSetMethods.jl