Release 2.2.0

• Added alternative parser implementation, pygerber.gerberx3.parser2.parser2.Parser2
  class.
• Added introspection interface based on new Parser2 class.
• Added macro support to Parser2 class which was not previously available in Parser
  class.
• Added API for customizing Token classes used by Tokenizer. Tokenizer class now
  accepts optional options parameter of class TokenizerOptions.
• Added documentation for introspection.
• Added experimental SVG backend for Gerber code with Parser2 generated command buffers.
• Changed documentation layout to improve readability.
• Fixed switching to single quadrant mode being ignored.
• Refactored feature support documentation.