I've added support for setting the fullscreen state of a window, as well as toggling it through a keypress. I now need to set fullscreen when client's request it.
Added fullscreen Doxygen comments.
Howm can now handle clients telling it when they want to be fullscreen or not.

I also fixed a subtle bug that meant that fullscreen windows weren't always focused.
I neatened up the client message code and made it easier to understand. I also added Doxygen comments for it.
Update README.md
Fixed some compiler warnings (hid unused param warnings).
When a gap's size is to be reduced below zero, set it to zero.
Update README.md

Add AUR packages. Thanks Alad!
Added a "nicer" way to kill clients.
I used the wrong atom name, fixed that and killing things nicely now works.
Disabled warnings when the root window is clicked.
Fixed killing multiple workspaces and using change_ws when it isn't needed. This should speed up killing workspaces.
Fixed the use of change_ws when moving a client to a different workspace.
Fixed not being able to kill the last workspace.
Prevented segfaults, killing multiple workspaces leads to infinite looping.
Neatened up the remove_client code that searches all clients on all workspaces.
Killing of multiple workspaces is now possible.
Update CONTRIBUTING.md
Update CONTRIBUTING.md
Added support for more client messages.