swaybar: Add support for Airblade i3bar extensions

This extends the i3bar protocol implementation with the following
features from @Airblade/i3:

* background
* border
* border_top, border_bottom, border_left, border_right

A block will now be rendered like this:

```
(border_left + margin) + width + (margin + border_right) + sep
```

Where `border_left/border_right` and their related margin is only drawn
if the `border` is specified and the border has a width > 0 (default is
1).

`border_top` and `border_bottom` does not affect the height of the bar
(no margin is added), thus it will be drawn behind the text if it is too
big. The user should specify a bar height if more space between
top/bottom borders are required.

0 files changed, 0 insertions, 0 deletions