anchor: Rasterizer:getGlyphData
  Gets glyph data of a specified glyph.
  glyphData = Rasterizer:getGlyphData( glyph )
  glyph string Glyph
  glyphData GlyphData Glyph data
  glyphData = Rasterizer:getGlyphData( glyphNumber )
  glyphNumber number Glyph number
  glyphData GlyphData Glyph data