Added TerminationGracePeriod field to PodSpec and grace-period flag to kubectl stop

Those are changes which touch users required by Termination Notice

Addresses #6804

docs/kubectl_delete.md

@@ -45,6 +45,7 @@ $ kubectl delete pods --all
       --all=false: [-all] to select all the specified resources
       --cascade=true: If true, cascade the delete resources managed by this resource (e.g. Pods created by a ReplicationController).  Default true.
   -f, --filename=[]: Filename, directory, or URL to a file containing the resource to delete
+      --grace-period=-1: Period of time in seconds given to the resource to terminate gracefully. Ignored if negative.
   -h, --help=false: help for delete
   -l, --selector="": Selector (label query) to filter on
 ```
@@ -82,4 +83,4 @@ $ kubectl delete pods --all
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-29 15:25:11.031169223 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-30 14:53:47.856200003 +0000 UTC

docs/kubectl_stop.md

@@ -35,6 +35,7 @@ $ kubectl stop -f path/to/resources
 ```
       --all=false: [-all] to select all the specified resources
   -f, --filename=[]: Filename, directory, or URL to file of resource(s) to be stopped
+      --grace-period=-1: Period of time in seconds given to the resource to terminate gracefully. Ignored if negative.
   -h, --help=false: help for stop
   -l, --selector="": Selector (label query) to filter on
 ```
@@ -72,4 +73,4 @@ $ kubectl stop -f path/to/resources
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-29 15:25:11.033329682 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-30 14:53:47.85772498 +0000 UTC

docs/man/man1/kubectl-delete.1

@@ -41,6 +41,10 @@ will be lost along with the rest of the resource.
 \fB\-f\fP, \fB\-\-filename\fP=[]
     Filename, directory, or URL to a file containing the resource to delete
 
+.PP
+\fB\-\-grace\-period\fP=\-1
+    Period of time in seconds given to the resource to terminate gracefully. Ignored if negative.
+
 .PP
 \fB\-h\fP, \fB\-\-help\fP=false
     help for delete

docs/man/man1/kubectl-stop.1

@@ -29,6 +29,10 @@ If the resource is resizable it will be resized to 0 before deletion.
 \fB\-f\fP, \fB\-\-filename\fP=[]
     Filename, directory, or URL to file of resource(s) to be stopped
 
+.PP
+\fB\-\-grace\-period\fP=\-1
+    Period of time in seconds given to the resource to terminate gracefully. Ignored if negative.
+
 .PP
 \fB\-h\fP, \fB\-\-help\fP=false
     help for stop