metadata-2 (#2273)

Initial implementation of draft/metadata-2

irc/metadata_test.go

@@ -0,0 +1,21 @@
+package irc
+
+import "testing"
+
+func TestKeyCheck(t *testing.T) {
+	cases := []struct {
+		input  string
+		isEvil bool
+	}{
+		{"ImNormal", false},
+		{":imevil", true},
+		{"key£with$not%allowed^chars", true},
+		{"key.that:s_completely/normal-and.fine", false},
+	}
+
+	for _, c := range cases {
+		if metadataKeyIsEvil(c.input) != c.isEvil {
+			t.Errorf("%s should have returned %v. but it didn't. so that's not great", c.input, c.isEvil)
+		}
+	}
+}