Felupe

Added
- Add kwargs of `field.extract()` to `fun` and `jac` of `newtonrhapson`.

Changed
- Set default number of `threads` in `MatadiMaterial` to `multiprocessing.cpu_count()`.
- Moved documentation to Read the Docs (Sphinx).

Fixed
- Fix `dim` in calculation of reaction forces (`tools.force`) for `FieldMixed`.
- Fix calculation of reaction moments (`tools.moment`) for `FieldMixed`.

Added
- Add `mask` argument to `Boundary` for the selection of user-defined points.
- Add `shear` loadcase.
- Add a wrapper for `matadi` materials as `MatadiMaterial`.
- Add `verbose` and `timing` arguments to `newtonrhapson`.

Fixed
- Obtain internal `dim` from Field in calculation of reaction force `tools.force`.
- Fix `math.dot` for combinations of rank 1 (vectors), rank 2 (matrices) and rank 4 tensors.

Changed
- Rename `mesh.as_discontinous()` to `mesh.disconnect()`.
- Rename `constitution.Mixed` to `constitution.ThreeFieldVariation`.
- Rename `unstack` to `offsets` as return of dof-partition and all subsequent references.
- Import tools (`newtonrhapson`, `project`, `save`) and constitution (`NeoHooke`, `LinearElastic` and `ThreeFieldVariation`) to FElupe's namespace.
- Change minimal README-example to a high-level code snippet and refer to docs for details.

Added
- Add template regions, i.e. a region with a `Hexahedron()` element and a quadrature scheme `GaussLegendre(order=1, dim=3)` as `RegionHexahedron`, etc.
- Add biaxial and planar loadcases (like uniaxial).
- Add a minimal README-example (Hello FElupe!).

Changed
- Deactivate clamped boundary (`clamped=False`) as default option for uniaxial loading `dof.uniaxial`.

Added
- Add inverse quadrature method `quadrature.inv()` for Gauss-Legendre schemes.
- Add discontinous representation of a mesh as mesh method `mesh.as_discontinous()`.
- Add `tools.project()` to project (and average) values at quadrature points to mesh points.

Changed
- Removed `quadpy` dependency and use built-in polynomials of `numpy` for Gauss-Legendre calculation.

Fixed
- Fix typo in first shear component of `math.tovoigt()` function.
- Fix wrong stress projection in `tools.topoints()` due to different quadrature and cell ordering.

Fixed
- Fix import of dof-module if `sparse` is not installed.