change font for documentation graphs

Doxyfile

@@ -1350,12 +1350,12 @@ HAVE_DOT               = YES
 # DOTFONTPATH environment variable or by setting DOT_FONTPATH to the directory 
 # containing the font.
 
-DOT_FONTNAME           = Verdana
+DOT_FONTNAME           = "Courier"
 
 # The DOT_FONTSIZE tag can be used to set the size of the font of dot graphs. 
 # The default size is 10pt.
 
-DOT_FONTSIZE           = 8
+DOT_FONTSIZE           = 9
 
 # By default doxygen will tell dot to use the output directory to look for the 
 # FreeSans.ttf font (which doxygen will put there itself). If you specify a