Add verbose output to docker build

Verbose output is enabled by default and
the flag -q can be used to suppress the verbose output.

commands.go

@@ -157,6 +157,8 @@ func mkBuildContext(dockerfile string, files [][2]string) (Archive, error) {
 func (cli *DockerCli) CmdBuild(args ...string) error {
 	cmd := Subcmd("build", "[OPTIONS] PATH | URL | -", "Build a new container image from the source code at PATH")
 	tag := cmd.String("t", "", "Tag to be applied to the resulting image in case of success")
+	suppressOutput := cmd.Bool("q", false, "Suppress verbose build output")
+
 	if err := cmd.Parse(args); err != nil {
 		return nil
 	}
@@ -194,6 +196,10 @@ func (cli *DockerCli) CmdBuild(args ...string) error {
 	// Upload the build context
 	v := &url.Values{}
 	v.Set("t", *tag)
+
+	if *suppressOutput {
+		v.Set("q", "1")
+	}
 	if isRemote {
 		v.Set("remote", cmd.Arg(0))
 	}