Added the launch for the simulation.

launch/blob_detector_sim.launch

+<!-- -->
+<launch>
+
+  <arg name="config_yaml_file" default="$(find iri_blob_detector)/config/default_params.yaml"/>
+
+  <node name="blob"
+        pkg="iri_blob_detector"
+        type="iri_blob_detector"
+        output="screen">
+    <param name="window_size" value="15"/>
+    <remap from="/blob/image_in/camera_info"
+             to="/usb_cam/camera_info"/>
+    <remap from="/blob/image_in/image_raw"
+             to="/usb_cam/image_raw"/>
+    <rosparam file="$(arg config_yaml_file)" command="load" />
+  </node>
+
+</launch>