Merge pull request microsoft#64 from wravery/master

Fix microsoft#63 - I re-ran the PR verification build and it [passed](https://dev.azure.com/wravery/Build%20Pipelines/_build/results?buildId=237)

Merge pull request microsoft#60 from wravery/master

Misc. updates to synch with latest PEGTL

Update to latest PEGTL commit

Merge pull request microsoft#49 from wravery/master

Couple of fixes

Fix microsoft#44 - Handle schema extensions

Merge pull request microsoft#40 from wravery/master

Fix microsoft#39, plus a lingering short-string-optimization bug

Fix microsoft#39, plus a lingering short-string-optimization bug

Merge pull request microsoft#38 from wravery/master

Fix issue microsoft#37

Merge pull request microsoft#36 from Microsoft/operationtypes

Expose findOperationDefinition to fix microsoft#34

Fix issue microsoft#37