Commands are 'mark' and 'goto'. Both can be used either directly,
like 'mark a' and 'goto a', or interactively (just 'mark'). For
interactive mode, i3-input must be installed and in your PATH.
Before this fix, you could go upwards and select the screen which
was at the rightmost because it also was the one topmost (if all
screen’s top position is equal).
Use bn (normal), bp (1-px), bb (borderless) as commands to change the
border style of the currently focused window. Feel free to use i3-msg
to do this.
Also update documentation (manpage, userguide).
To make the code easier to read/write when checking if a client is
floating, introduce client_is_floating().