Summary:
* Fix bold lines (BUG 402415).
* Make drawing pixel-perfect.
* Make line width proportional to font size.
* Move relevant code to separate file and namespace.
* Remove code for checking supported line characters from Character
  class. Information about what is supported is now in one place
  together width drawing code.
* Remove fontembedder/LineFont files (no longer used).
* Add test script for displaying supported characters table.
* Add triple and quadruple dashes (U+2504...U+250B).
* Change shade block characters (U+2591...U+2593) look. When
  antialiasing is turned on, shades are drawn as transculent solid
  rectangles with 25%, 50% and 75% alpha. This matches the characters
  name/description and their usage. Without antialiasing, previous
  method with patterns is used.

**Screenshots**

Font size: 10pt; character width: 8px
{F6602823}

Font size: 11pt; character width: 9px
{F6602824}

Font size: 12pt; character width: 10px
{F6602825}

Font s...