Treeview triangles

When the triangle glyphs aren't available (as is the case on certain
platforms, unless we distribute the glyphs ourselves), the treeviews don't
look satisfactory.

As an alternative, I could just draw triangles with the polygon plotter.

There are a few drawbacks with this:

- Triangle has to have dimensions which are even or the
triangle will look lopsided.
- Polygon plotter may not anti-alias.

You can see how they would look on this page, where I've faked them up
with borders that NetSurf plots via the polygon plotter:

http://www.netsurf-browser.org/temp/treeview/triangles.html

Any thoughts?

--

Michael Drake (tlsa) http://www.netsurf-browser.org/