Failure to parse ZEROBASEDSTRINGS compiler directive

[d-c-d]

The examples that come with the Object Pascal Handbook yield the following parse error

	Unrecognized compiler directive 'ZEROBASEDSTRINGS' (1)
		.\StringMetaTestForm.pas:651

The offending line in ObjectPascalHandbook/06/StringMetaTest/StringMetaTestForm.pas is 31:{$ZEROBASEDSTRINGS ON}

This example can be found here on github: https://github.com/MarcoDelphiBooks/ObjectPascalHandbook/tree/master/06/StringMetaTest ZEROBASEDSTRINGS is described here: http://docwiki.embarcadero.com/RADStudio/Rio/en/Zero-based_strings_(Delphi)

Assuming that we need to add _directiveTypes["ZEROBASEDSTRINGS"] = DirectiveType.Ignored; to the TokenFilter constructor in TokenFilter.cs