Fix and tune things, add tool "recharge" animation, add dummyball

data/builtin.lua

data/mods/default/init.lua

data/mods/experimental/init.lua

data/mods/experimental/textures/experimental_dummyball.png

src/camera.cpp

src/camera.h

src/content_cao.cpp

src/content_sao.cpp

src/game.cpp

src/tool.h