clx: medium: fix a few problems with the line style
clx: medium: fix a few problems with the line style

- use line-style-effective-thickness in medium-draw-point(s)*

  Until now we've used the line-style-thickness which was wrong
  because when the line unit is not "normal" then we need to scale the
  thickness (that was done for medium-draw-line(s)*)

- update the line thickness when the medium-transformation changes

  Otherwise when the line unit is :coordinate the following snippets
  give different results:

    (with-drawing-options (pane :line-unit :coordinate :line-thickness 1)
      (with-scaling (pane 5)
        (clim:draw-rectangle* pane 10 10 90 90 :filled nil)))

    (with-scaling (pane 5)
      (with-drawing-options (pane :line-unit :coordinate :line-thickness 1)
        (clim:draw-rectangle* pane 10 10 90 90 :filled nil)))

- add a function translate-join-shape (similar to already existing
  function translate-cap-shape) -- also warn the user when the join
  style is not supported by clx and default to :miter

  Previously when we've used a style :none which is specified in CLIM
  we've had an error from CLX that it is an invalid value

- medium-draw-points* uses the same pixel pattern for drawn points

Co-authored-by: Jan Moringen <ff5fc50d47d2b1a344dbccbe82bad109f52b310d@techfak.uni-bielefeld.de>

slyrus/mcclim,slyrus/mcclim