The renderer now only stores the positions of the actions because that
is specific to the renderer and because the actual position can only be
finalized after all the rendering is done because intitially the
positions are relative to the alignment and not the bar.
The variables storing the current colors, attribute activations and font
were only used in a single place and can easily also be read from the
context.
This allows us to remove a lot of the state of the renderer.
The %{PR} tag is introduced for this. It resets all colors as well as
the activation of the underline and overline and font.
This has become necessary because we don't track what raw tags a user
injects into the formatting string and otherwise their raw tags could
bleed through.
This doesn't touch action tags because even before raw action tags
weren't being tracked. Action tags also have the requirement that they
have to be used in pairs, so closing them prematurely could break things
(for example with click actions for the entire bar)
We now take the bar position that the window manager gives us instead of trying
to calculate it ourselves. This is more correct when multiple bars are attached
to the same edge, as the window manager may move some of them in that
case (assuming override redirect is not enabled)
