Fixed frame widget area resizing bug

  - The vertical space needs to take the horizontal scroll bar into
    account if present
  - The code mistakenly checked if the vertical one needed drawing
    insead
Fixed font cache bug

  - Glyphs with only 1 pixel with or height (e.g. pipe, underscore, ...)
    ended up not being rendered because of zero with box
  - Added "fudge factor" in font cache code