[css-fonts-3] i18n-ISSUE-287: Figure 4 - combining diacritics

http://www.w3.org/TR/2013/WD-css-fonts-3-20130711/#typography-background
Typography Background

Figure 4 & "The use of combining diacritic marks creates many variations 
for an underlying letterform"

Not sure what is the intent of fig 4. If it's to show how a font has to 
cater for variation in placement and shape of glyphs, it might be better 
to use examples of tone marks in Thai and medial consonants in Burmese, 
etc. I can supply examples if needed.

This would also introduce the idea of complex scripts, which I thought 
was lacking in this section.