Add ListFlavors() and acceptance test.

This is required to support server creation acceptance testing.  Without
the ability to detect flavors automatically, it isn't possible to
automate acceptance testing, as then a human operator would be required
to manually intervene while testing.
diff --git a/acceptance/06-list-flavors.go b/acceptance/06-list-flavors.go
new file mode 100644
index 0000000..ad56988
--- /dev/null
+++ b/acceptance/06-list-flavors.go
@@ -0,0 +1,48 @@
+package main
+
+import (
+	"fmt"
+	"flag"
+	"github.com/rackspace/gophercloud"
+)
+
+var quiet = flag.Bool("quiet", false, "Quiet mode for acceptance testing.  $? non-zero on error though.")
+var rgn = flag.String("r", "DFW", "Datacenter region to interrogate.")
+
+func main() {
+	provider, username, password := getCredentials()
+	flag.Parse()
+
+	auth, err := gophercloud.Authenticate(
+		provider,
+		gophercloud.AuthOptions{
+			Username: username,
+			Password: password,
+		},
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	servers, err := gophercloud.ServersApi(auth, gophercloud.ApiCriteria{
+		Name:      "cloudServersOpenStack",
+		Region:    *rgn,
+		VersionId: "2",
+		UrlChoice: gophercloud.PublicURL,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	flavors, err := servers.ListFlavors()
+	if err != nil {
+		panic(err)
+	}
+
+	if !*quiet {
+		fmt.Println("ID,Name,MinRam,MinDisk")
+		for _, f := range flavors {
+			fmt.Printf("%s,\"%s\",%d,%d\n", f.Id, f.Name, f.Ram, f.Disk)
+		}
+	}
+}