Move unported exampels to unported-examples

unported-examples/gas_dynamics/wing.py

unported-examples/geometry.py

unported-examples/heat/heat.py

unported-examples/maxwell/.gitignore

unported-examples/maxwell/cavities.py

unported-examples/maxwell/dipole.py

unported-examples/maxwell/generate-bessel-zeros.py

unported-examples/maxwell/inhom-cavity.py

unported-examples/maxwell/inhomogeneous_waveguide.mac

unported-examples/maxwell/maxwell-2d.py

unported-examples/maxwell/maxwell-pml.py

unported-examples/maxwell/notes.tm

unported-examples/poisson/helmholtz.py

unported-examples/poisson/poisson.py