standalone_complexed_nodelet: add params key for each nodelet

[furushchev]

   nodelets:
     -  name: node_name
        type: nodelet_type
        remappings:
          - from: from_topic
            to: to_topic
          - from: from_topic
            to: to_topic
        params:  # This is supported in this PR.
          - name: approximate_sync
            value: true
          - name: queue_size
            value: 100
     -  name: node_name2
        type: nodelet_type2
        if: false
     -  name: node_name3
        type: nodelet_type3
        unless: false

[k-okada]

@furushchev please add more info. who uses this feature?

[furushchev]

@k-okada Okay, standalone_complexed_nodelet is a workaround for the issue #1531 and is, for example, used on demo packages for stability.

Using an example above, formerly we had to create a launch file likw as followings:

<launch>
  <node name="manager" pkg="jsk_topic_tools" type="standalone_complexed_nodelet">
    <rosparam>
   nodelets:
     -  name: node1
        type: nodelet_type
        remappings:
          - from: from_topic
            to: to_topic
          - from: from_topic
            to: to_topic
     -  name: node2
        type: nodelet_type2
        if: false
     -  name: node3
        type: nodelet_type3
        unless: false
    </rosparam>
  </node>

  <rosparam ns="node1">
   approximate_sync: true
   queue_size: 100
  </rosparam>
</launch>

There, parameters are defined separately from declaration of nodelets.

[knorth55]

PR2 uses this feature.