Webmention endpoint-discovery conformance run for IndyWeb-Go issue #43.

Discovery test 1: test 1

Discovery test 2: test 2

Discovery test 3: test 3

Discovery test 4: test 4

Discovery test 5: test 5

Discovery test 6: test 6

Discovery test 7: test 7

Discovery test 8: test 8

Discovery test 9: test 9

Discovery test 10: test 10

Discovery test 11: test 11

Discovery test 12: test 12

Discovery test 13: test 13

Discovery test 14: test 14

Discovery test 15: test 15

Discovery test 16: test 16

Discovery test 17: test 17

Discovery test 18: test 18

Discovery test 19: test 19

Discovery test 20: test 20

Discovery test 21: test 21

Discovery test 22: test 22

Discovery test 23: test 23