Interface sources on GPU, examples, documentation.

doc/changelog.md

doc/compile.md

doc/lua_api.md

include/maxwell_common.h

include/maxwell_interface.h

share/binde_simplified/binde_simplified.geo

share/binde_simplified/params_binde_simplified.lua

share/modeconv/modeconv.geo

share/modeconv/modeconv.i1

share/modeconv/params_modeconv.lua

share/yagi/params_yagi.lua

share/yagi/yagi.geo

src/maxwell_cpu.cpp

src/maxwell_gpu.cpp

src/maxwell_solver.cpp