Resolve "Build images in individual stages"

Closes #33

See merge request mechanics-and-materials/ae108!32

Resolve "Convert periodic boundary conditions to affine transform"

Closes #27

See merge request mechanics-and-materials/ae108!24

- images are now built in sequence

- throw InvalidVertexException for invalid vertex indices

- reports that an invalid vertex has been provided

- uses the TransformingSolver to enforce boundary conditions

- creates the AffineTransform needed by the TransformingSolver

- reports that a collection of GeneralizedMeshBoundaryConditions is inconsistent

- determines the location of data in a global/distributed vector

- this class can be used to specify e.g. periodic boundary conditions

Resolve "Return empty mesh for zero `granularity`"

Closes #30

See merge request mechanics-and-materials/ae108!30

Resolve "Integrate force over subset of vertices"

Closes #26

See merge request mechanics-and-materials/ae108!29

Resolve "Add functions to mesh a cuboid with (linear/quadratic) tetrahedra"

Closes #29

See merge request mechanics-and-materials/ae108!28

Resolve "Reduce number of layers in Docker image"

Closes #28

See merge request mechanics-and-materials/ae108!27

Resolve "Add quadrature rules for tetrahedra"

Closes #25

See merge request mechanics-and-materials/ae108!23

Resolve "Add Tet10"

Closes #24

See merge request mechanics-and-materials/ae108!26

Resolve "Add Tet4 element"

Closes #23

See merge request mechanics-and-materials/ae108!25

Resolve "Add Tri6 element"

Closes #22

See merge request mechanics-and-materials/ae108!22