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)
+		}
+	}
+}
diff --git a/flavors.go b/flavors.go
index 909a308..22c13c4 100644
--- a/flavors.go
+++ b/flavors.go
@@ -1,5 +1,24 @@
 package gophercloud
 
+import (
+	"github.com/racker/perigee"
+)
+
+// See CloudServersProvider interface for details.
+func (gsp *genericServersProvider) ListFlavors() ([]Flavor, error) {
+	var fs []Flavor
+
+	url := gsp.endpoint + "/flavors"
+	err := perigee.Get(url, perigee.Options{
+		CustomClient: gsp.context.httpClient,
+		Results:      &struct{ Flavors *[]Flavor }{&fs},
+		MoreHeaders: map[string]string{
+			"X-Auth-Token": gsp.access.AuthToken(),
+		},
+	})
+	return fs, err
+}
+
 // FlavorLink provides a reference to a flavor by either ID or by direct URL.
 // Some services use just the ID, others use just the URL.
 // This structure provides a common means of expressing both in a single field.
@@ -7,3 +26,28 @@
 	Id    string `json:"id"`
 	Links []Link `json:"links"`
 }
+
+// Flavor records represent (virtual) hardware configurations for server resources in a region.
+//
+// The Id field contains the flavor's unique identifier.
+// For example, this identifier will be useful when specifying which hardware configuration to use for a new server instance.
+//
+// The Disk and Ram fields provide a measure of storage space offered by the flavor, in GB and MB, respectively.
+//
+// The Name field provides a human-readable moniker for the flavor.
+//
+// Swap indicates how much space is reserved for swap.
+// If not provided, this field will be set to 0.
+//
+// VCpus indicates how many (virtual) CPUs are available for this flavor.
+type Flavor struct {
+	OsFlvDisabled bool    `json:"OS-FLV-DISABLED:disabled"`
+	Disk          int     `json:"disk"`
+	Id            string  `json:"id"`
+	Links         []Link  `json:"links"`
+	Name          string  `json:"name"`
+	Ram           int     `json:"ram"`
+	RxTxFactor    float64 `json:"rxtx_factor"`
+	Swap          int     `json:"swap"`
+	VCpus         int     `json:"vcpus"`
+}
diff --git a/interfaces.go b/interfaces.go
index ee02baf..649e756 100644
--- a/interfaces.go
+++ b/interfaces.go
@@ -26,5 +26,9 @@
   // Images
 
   ListImages() ([]Image, error)
+
+  // Flavors
+
+  ListFlavors() ([]Flavor, error)
 }