vector: reduce SMALL_TEXT font height 6 -> 5 to be more like raster;

reduce antialiasing allowance for `textoffset`;
  adjust text to baseline using values for Arimo rather than
  percentage
GUI: fix not enabling font combo "Small Bold (vector only)" by
  default
raster/vector: rename `text_height` -> `font_height`

docs/images/dbar_exp.svg

@@ -1,11 +1,11 @@
 <?xml version="1.0" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg width="961" height="209" version="1.1" xmlns="http://www.w3.org/2000/svg">
+<svg width="961" height="203" version="1.1" xmlns="http://www.w3.org/2000/svg">
  <desc>Zint Generated Symbol</desc>
  <g id="barcode" fill="#000000">
-  <rect x="0" y="0" width="961" height="209" fill="#FFFFFF"/>
+  <rect x="0" y="0" width="961" height="203" fill="#FFFFFF"/>
   <path d="M4.8 0h4.8v163.2h-4.8ZM19.2 0h4.8v163.2h-4.8ZM43.2 0h9.6v163.2h-9.6ZM67.2 0h9.6v163.2h-9.6ZM81.6 0h9.6v163.2h-9.6ZM96 0h38.4v163.2h-38.4ZM153.6 0h4.8v163.2h-4.8ZM163.2 0h14.4v163.2h-14.4ZM196.8 0h9.6v163.2h-9.6ZM216 0h4.8v163.2h-4.8ZM225.6 0h4.8v163.2h-4.8ZM244.8 0h9.6v163.2h-9.6ZM259.2 0h4.8v163.2h-4.8ZM292.8 0h9.6v163.2h-9.6ZM316.8 0h4.8v163.2h-4.8ZM326.4 0h4.8v163.2h-4.8ZM336 0h28.8v163.2h-28.8ZM384 0h14.4v163.2h-14.4ZM403.2 0h4.8v163.2h-4.8ZM417.6 0h14.4v163.2h-14.4ZM460.8 0h4.8v163.2h-4.8ZM475.2 0h4.8v163.2h-4.8ZM484.8 0h4.8v163.2h-4.8ZM499.2 0h24v163.2h-24ZM528 0h14.4v163.2h-14.4ZM552 0h9.6v163.2h-9.6ZM576 0h28.8v163.2h-28.8ZM624 0h4.8v163.2h-4.8ZM633.6 0h14.4v163.2h-14.4ZM652.8 0h9.6v163.2h-9.6ZM686.4 0h4.8v163.2h-4.8ZM700.8 0h4.8v163.2h-4.8ZM715.2 0h4.8v163.2h-4.8ZM734.4 0h19.2v163.2h-19.2ZM763.2 0h4.8v163.2h-4.8ZM772.8 0h9.6v163.2h-9.6ZM796.8 0h4.8v163.2h-4.8ZM806.4 0h38.4v163.2h-38.4ZM854.4 0h14.4v163.2h-14.4ZM883.2 0h9.6v163.2h-9.6ZM897.6 0h19.2v163.2h-19.2ZM921.6 0h4.8v163.2h-4.8ZM945.6 0h4.8v163.2h-4.8ZM955.2 0h4.8v163.2h-4.8Z"/>
-  <text x="480" y="196.8" text-anchor="middle" font-family="Arimo, Arial, sans-serif" font-size="33.6">
+  <text x="480" y="195.23" text-anchor="middle" font-family="Arimo, Arial, sans-serif" font-size="33.6">
    (01)98898765432106(3202)012345(15)991231
   </text>
  </g>