Merge pull request #4672 from vieux/update_godoc_mflags

update godoc and add MAINTAINERS for mflags

pkg/mflag/MAINTAINERS

@@ -0,0 +1 @@
+Victor Vieux <victor.vieux@docker.com> (@vieux)

pkg/mflag/flag.go

@@ -10,7 +10,7 @@
 	Define flags using flag.String(), Bool(), Int(), etc.
 
 	This declares an integer flag, -f or --flagname, stored in the pointer ip, with type *int.
-		import "flag"
+		import "flag /github.com/dotcloud/docker/pkg/mflag"
 		var ip = flag.Int([]string{"f", "-flagname"}, 1234, "help message for flagname")
 	If you like, you can bind the flag to a variable using the Var() functions.
 		var flagvar int
@@ -23,6 +23,18 @@
 		flag.Var(&flagVal, []string{"name"}, "help message for flagname")
 	For such flags, the default value is just the initial value of the variable.
 
+	You can also add "deprecated" flags, they are still usable, bur are not shown
+	in the usage and will display a warning when you try to use them:
+		var ip = flag.Int([]string{"f", "#flagname", "-flagname"}, 1234, "help message for flagname")
+	this will display: `Warning: '-flagname' is deprecated, it will be replaced by '--flagname' soon. See usage.` and
+		var ip = flag.Int([]string{"f", "#flagname"}, 1234, "help message for flagname")
+	will display: `Warning: '-t' is deprecated, it will be removed soon. See usage.`
+
+	You can also group one letter flags, bif you declare
+		var v = flag.Bool([]string{"v", "-verbose"}, false, "help message for verbose")
+		var s = flag.Bool([]string{"s", "-slow"}, false, "help message for slow")
+	you will be able to use the -vs or -sv
+
 	After all flags are defined, call
 		flag.Parse()
 	to parse the command line into the defined flags.