Support extended pod logging options

Increase the supported controls on pod logging. Add validaiton to pod
log options. Ensure the Kubelet is using a consistent, structured way to
process pod log arguments.

Add ?sinceSeconds=<durationInSeconds>, &sinceTime=<RFC3339>, ?timestamps=<bool>,
?tailLines=<number>, and ?limitBytes=<number>

pkg/kubectl/cmd/util/helpers.go

@@ -260,6 +260,15 @@ func GetFlagInt(cmd *cobra.Command, flag string) int {
 	return i
 }
 
+// Assumes the flag has a default value.
+func GetFlagInt64(cmd *cobra.Command, flag string) int64 {
+	i, err := cmd.Flags().GetInt64(flag)
+	if err != nil {
+		glog.Fatalf("err accessing flag %s for command %s: %v", flag, cmd.Name(), err)
+	}
+	return i
+}
+
 func GetFlagDuration(cmd *cobra.Command, flag string) time.Duration {
 	d, err := cmd.Flags().GetDuration(flag)
 	if err != nil {