cmd/swarm: allow uploading from stdin (#3744)

- intended to be a swarm alternative to termbin.com
- added --stdin flag to swarm executable. if set, swarm will
  read data from stdin and postRaw it.

cmd/swarm/main.go

@@ -112,6 +112,14 @@ var (
 		Name:  "defaultpath",
 		Usage: "path to file served for empty url path (none)",
 	}
+	SwarmUpFromStdinFlag = cli.BoolFlag{
+		Name:  "stdin",
+		Usage: "reads data to be uploaded from stdin",
+	}
+	SwarmUploadMimeType = cli.StringFlag{
+		Name:  "mime",
+		Usage: "force mime type",
+	}
 	CorsStringFlag = cli.StringFlag{
 		Name:  "corsdomain",
 		Usage: "Domain on which to send Access-Control-Allow-Origin header (multiple domains can be supplied separated by a ',')",
@@ -244,6 +252,8 @@ Cleans database of corrupted entries.
 		SwarmRecursiveUploadFlag,
 		SwarmWantManifestFlag,
 		SwarmUploadDefaultPath,
+		SwarmUpFromStdinFlag,
+		SwarmUploadMimeType,
 	}
 	app.Flags = append(app.Flags, debug.Flags...)
 	app.Before = func(ctx *cli.Context) error {