Merge branch 'update-doc'

CHANGELOG.md

README.md

doc/img/Lebwohl_Lasher.png

doc/img/box.png

doc/img/coupling.png

doc/img/gauge_model_hamiltonian.png

doc/img/gauge_symmetry.png

doc/img/gaussian.png

doc/img/global_symmetry.png

doc/img/lorentzian.png

frustmag/README.md

frustmag/params/.gitignore

frustmag/params/kagome.ini

frustmag/params/kagome_hot.ini

gauge/README.md

gauge/params/.gitignore

gauge/params/Cinfv-hyperplane.ini

gauge/params/D2h-cycle.ini

gauge/params/D2h-grid.ini

gauge/params/D2h-phase-diagram.ini