Portworx Volume Driver in Kubernetes

- Add a new type PortworxVolumeSource
- Implement the kubernetes volume plugin for Portworx Volumes under pkg/volume/portworx
- The Portworx Volume Driver uses the libopenstorage/openstorage specifications and apis for volume operations.

Changes for k8s configuration and examples for portworx volumes.

- Add PortworxVolume hooks in kubectl, kube-controller-manager and validation.
- Add a README for PortworxVolume usage as PVs, PVCs and StorageClass.
- Add example spec files

Handle code review comments.

- Modified READMEs to incorporate to suggestions.
- Add a test for ReadWriteMany access mode.
- Use util.UnmountPath in TearDown.
- Add ReadOnly flag to PortworxVolumeSource
- Use hostname:port instead of unix sockets
- Delete the mount dir in TearDown.
- Fix link issue in persistentvolumes README
- In unit test check for mountpath after Setup is done.
- Add PVC Claim Name as a Portworx Volume Label

Generated code and documentation.
- Updated swagger spec
- Updated api-reference docs
- Updated generated code under pkg/api/v1

Godeps update for Portworx Volume Driver
- Adds github.com/libopenstorage/openstorage
- Adds go.pedge.io/pb/go/google/protobuf
- Updates Godep Licenses

pkg/api/zz_generated.deepcopy.go

@@ -158,6 +158,7 @@ func RegisterDeepCopies(scheme *runtime.Scheme) error {
 		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_PodTemplate, InType: reflect.TypeOf(&PodTemplate{})},
 		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_PodTemplateList, InType: reflect.TypeOf(&PodTemplateList{})},
 		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_PodTemplateSpec, InType: reflect.TypeOf(&PodTemplateSpec{})},
+		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_PortworxVolumeSource, InType: reflect.TypeOf(&PortworxVolumeSource{})},
 		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_Preconditions, InType: reflect.TypeOf(&Preconditions{})},
 		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_PreferAvoidPodsEntry, InType: reflect.TypeOf(&PreferAvoidPodsEntry{})},
 		conversion.GeneratedDeepCopyFunc{Fn: DeepCopy_api_PreferredSchedulingTerm, InType: reflect.TypeOf(&PreferredSchedulingTerm{})},
@@ -2059,6 +2060,11 @@ func DeepCopy_api_PersistentVolumeSource(in interface{}, out interface{}, c *con
 			*out = new(PhotonPersistentDiskVolumeSource)
 			**out = **in
 		}
+		if in.PortworxVolume != nil {
+			in, out := &in.PortworxVolume, &out.PortworxVolume
+			*out = new(PortworxVolumeSource)
+			**out = **in
+		}
 		return nil
 	}
 }
@@ -2557,6 +2563,15 @@ func DeepCopy_api_PodTemplateSpec(in interface{}, out interface{}, c *conversion
 	}
 }
 
+func DeepCopy_api_PortworxVolumeSource(in interface{}, out interface{}, c *conversion.Cloner) error {
+	{
+		in := in.(*PortworxVolumeSource)
+		out := out.(*PortworxVolumeSource)
+		*out = *in
+		return nil
+	}
+}
+
 func DeepCopy_api_Preconditions(in interface{}, out interface{}, c *conversion.Cloner) error {
 	{
 		in := in.(*Preconditions)
@@ -3447,6 +3462,11 @@ func DeepCopy_api_VolumeSource(in interface{}, out interface{}, c *conversion.Cl
 				return err
 			}
 		}
+		if in.PortworxVolume != nil {
+			in, out := &in.PortworxVolume, &out.PortworxVolume
+			*out = new(PortworxVolumeSource)
+			**out = **in
+		}
 		return nil
 	}
 }