Ansible script: Improve comments, add alsamixer.

[config] / ansible / files / apt-mark / 3d_acceleration

bumblebee-nvidia
libgl1-mesa-dri  # tested as necessary for OpenGL 3D acceleration to work
libglu1-mesa  # tested as necessary for OpenGL 3D acceleration to work
linux-headers-amd64  # tested as necessary to build proper nvidia-driver module
primus  # bridge by which bumblebee will deliver Nvidia-renderend content to Intel card