anchor: Rasterizer:hasGlyphs
  Checks if font contains specified glyphs.
  hasGlyphs = Rasterizer:hasGlyphs( glyph1, glyph2, ... )
  glyph1 string or number Glyph
  glyph2 string or number Glyph
  ... string or number Additional glyphs
  hasGlyphs boolean Whatever font contains specified glyphs.