I3-gaps

Building on pi

sudo apt-get install xcb libx11-xcb-dev libxcb-keysyms1-dev libsdl-pango-dev libxcb1-dev libxcb-keysyms1-dev libpango1.0-dev libxcb-util0-dev libxcb-icccm4-dev libyajl-dev libstartup-notification0-dev libxcb-randr0-dev libev-dev libxcb-cursor-dev libxcb-xinerama0-dev libxcb-xkb-dev libxkbcommon-dev libxkbcommon-x11-dev

cd development
git clone https://www.github.com/Airblader/i3 i3-gaps
cd i3-gaps
make

Then reboot and pick as window manager.