Added support for os-floating-ips extension

This commit adds support for the os-floating-ips extention. This allows
users to allocate and deallocate floating IPs as well as have instances
associate and disassociate floating IPs in a nova-network based cloud.
diff --git a/openstack/compute/v2/extensions/floatingip/requests.go b/openstack/compute/v2/extensions/floatingip/requests.go
new file mode 100644
index 0000000..ab681dc
--- /dev/null
+++ b/openstack/compute/v2/extensions/floatingip/requests.go
@@ -0,0 +1,111 @@
+package floatingip
+
+import (
+	"errors"
+
+	"github.com/racker/perigee"
+	"github.com/rackspace/gophercloud"
+	"github.com/rackspace/gophercloud/pagination"
+)
+
+// List returns a Pager that allows you to iterate over a collection of FloatingIPs.
+func List(client *gophercloud.ServiceClient) pagination.Pager {
+	return pagination.NewPager(client, listURL(client), func(r pagination.PageResult) pagination.Page {
+		return FloatingIPsPage{pagination.SinglePageBase(r)}
+	})
+}
+
+// CreateOptsBuilder describes struct types that can be accepted by the Create call. Notable, the
+// CreateOpts struct in this package does.
+type CreateOptsBuilder interface {
+	ToFloatingIPCreateMap() (map[string]interface{}, error)
+}
+
+// CreateOpts specifies a Floating IP allocation request
+type CreateOpts struct {
+	// Pool is the pool of floating IPs to allocate one from
+	Pool string
+}
+
+// ToFloatingIPCreateMap constructs a request body from CreateOpts.
+func (opts CreateOpts) ToFloatingIPCreateMap() (map[string]interface{}, error) {
+	if opts.Pool == "" {
+		return nil, errors.New("Missing field required for floating IP creation: Pool")
+	}
+
+	return map[string]interface{}{"pool": opts.Pool}, nil
+}
+
+// Create requests the creation of a new floating IP
+func Create(client *gophercloud.ServiceClient, opts CreateOptsBuilder) CreateResult {
+	var res CreateResult
+
+	reqBody, err := opts.ToFloatingIPCreateMap()
+	if err != nil {
+		res.Err = err
+		return res
+	}
+
+	_, res.Err = perigee.Request("POST", createURL(client), perigee.Options{
+		MoreHeaders: client.AuthenticatedHeaders(),
+		ReqBody:     reqBody,
+		Results:     &res.Body,
+		OkCodes:     []int{200},
+	})
+	return res
+}
+
+// Get returns data about a previously created FloatingIP.
+func Get(client *gophercloud.ServiceClient, id string) GetResult {
+	var res GetResult
+	_, res.Err = perigee.Request("GET", getURL(client, id), perigee.Options{
+		MoreHeaders: client.AuthenticatedHeaders(),
+		Results:     &res.Body,
+		OkCodes:     []int{200},
+	})
+	return res
+}
+
+// Delete requests the deletion of a previous allocated FloatingIP.
+func Delete(client *gophercloud.ServiceClient, id string) DeleteResult {
+	var res DeleteResult
+	_, res.Err = perigee.Request("DELETE", deleteURL(client, id), perigee.Options{
+		MoreHeaders: client.AuthenticatedHeaders(),
+		OkCodes:     []int{202},
+	})
+	return res
+}
+
+// association / disassociation
+
+// Associate pairs an allocated floating IP with an instance
+func Associate(client *gophercloud.ServiceClient, serverId, fip string) AssociateResult {
+	var res AssociateResult
+
+	addFloatingIp := make(map[string]interface{})
+	addFloatingIp["address"] = fip
+	reqBody := map[string]interface{}{"addFloatingIp": addFloatingIp}
+
+	_, res.Err = perigee.Request("POST", associateURL(client, serverId), perigee.Options{
+		MoreHeaders: client.AuthenticatedHeaders(),
+		ReqBody:     reqBody,
+		OkCodes:     []int{202},
+	})
+	return res
+}
+
+// Disassociate decouples an allocated floating IP from an instance
+func Disassociate(client *gophercloud.ServiceClient, serverId, fip string) DisassociateResult {
+	var res DisassociateResult
+
+	removeFloatingIp := make(map[string]interface{})
+	removeFloatingIp["address"] = fip
+	reqBody := map[string]interface{}{"removeFloatingIp": removeFloatingIp}
+
+	_, res.Err = perigee.Request("POST", disassociateURL(client, serverId), perigee.Options{
+		MoreHeaders: client.AuthenticatedHeaders(),
+		ReqBody:     reqBody,
+		OkCodes:     []int{202},
+	})
+	return res
+}