Build on Ubuntu 20.04

sudo apt -y install libbullet-dev libassimp-dev liblua5.2-dev libluabind-dev  \
                    libqglviewer-headers libqglviewer-dev-qt5 freeglut3-dev libglew-dev \
                    libsdl2-dev git g++

The build on Ubuntu 20.04 compiles fine, but fails to run with an assertion, see issue #11 for that failing assertion in luabind.