Add a parsing benchmark.

benchmark/output.json

Index: benchmark/output.json
diff --git a/benchmark/output.json b/benchmark/output.json
new file mode 100644
index 0000000000000000000000000000000000000000..054cef7cff1dd117d11ea85038add6458d22c049
--- /dev/null
+++ b/benchmark/output.json
@@ -0,0 +1 @@
+{"verb":"RecommendCafes","recipe":[{"outputs":["Cafe[]"],"verb":"List"},{"outputs":["CafeWithMenu[]"],"verb":"Fetch","inputs":["Cafe[]"]},{"outputs":["DishOffering[]"],"verb":"Flatten","inputs":["CafeWithMenu[]"]},{"outputs":["DishOffering[]/Scored"],"verb":"Score","inputs":["DishOffering[]"]},{"verb":"Display","inputs":["DishOffering[]/Scored"]}],"tags":{"numbers":[{"int":12345},{"negative":-345},{"floating-point":345.678},{"hexidecimal":1194684},{"exponential":1230.15},{"octal":12}],"dates":[{"canonical":"2001-12-15T02:59:43.1Z"},{"iso8601":"2001-12-14t21:59:43.10-05:00"},{"spaced":"2001-12-14 21:59:43.10 -5"},{"date":"2002-12-14"}],"strings":[{"unicode":"Sosa did fine.☺"},{"control":"\b1998\t1999\t2000\n"},{"hex esc":"\r\n is \r\n"},{"single":"\"Howdy!\" he cried."},{"quoted":" # Not a 'comment'."},{"tie-fighter":"|\\-*-/|"},{"plain":"This unquoted scalar spans many lines."},{"quoted":"So does this quoted scalar.\n"},{"accomplishment":"Mark set a major league home run record in 1998.\n"},{"stats":"65 Home Runs\n0.278 Batting Average\n"}],"booleans":[true,false]}}