implement up and down keys to navigate in the chat history, needs testing over network
do not hardcode CMAKE_INSTALL_PREFIX for windows, but rather put it in the script, so that custom build setups still work
Hard math to fix
issue #571. Well, not really hard math,
just checking if vector is in opposite direction and trait
that as a special case when removing rope dividing point
(this could only happens when rope sticks to land outline,
so this basically fixes a bug in another bug).