1.5.1

• Adds a getAllowedValues method to the interface, which returns the
  allowed values for options - so consumers can use that instead of copy
  pasting from the documentation.
• Restructures the 'named style' mechanism. No interface changes, just a
  preparation to be able to expand named styles to more than css only
• Improvements to the 'fountainpen' experimental style.
• Optimalizations in the css that is included in all generated svg's
• ⬆️ pegjs, lodash and some development dependencies

All changes since 1.5.0: 1.5.0...1.5.1