HaikuDepot: Give access to glyph spacing

 * The implementation for the get-accessors was missing
   from CharacterStyle.
HaikuDepot: Text stuff: Added line spacing to ParagraphStyle
HaikuDepot: List: Changed parameter order for Replace()

  (index first)
HaikuDepot: Text stuff: Switched from TextStyle to CharacterStyle
HaikuDepot: Text stuff: ParagraphLayout compiles and maybe works
HaikuDepot: CharacterStyle: Added convenience methods
HaikuDepot: TextDocument: Added Paragraph access by index.
HaikuDepot: ParagraphLayout: Debugged and now working.

 * The biggest problem was that adding the wrapped
   sub-TextSpan to the LineInfos was missing. Other
   problems included missing handling of ascent and
   descent per CharacterStyle.
HaikuDepot: New TextDocumentView and test app.

 * TextDocumentView still only shows the first paragraph
   of a TextDocument, but this time using the new
   ParagraphLayout. A class for layouting all paragraphs
   of a TextDocument is up next.
 * A simple test app shows that TextSpans with different
   CharacterStyles already work in one Paragraph. The test
   is nowhere extensive and does not test for bugs in
   corner cases.