add ROS_PACKAGE_PATH in environment (resolves #348)

README.md

@@ -162,6 +162,7 @@ Currently, this layer is still under continuous development.
 
     export ROS_ROOT=/opt/ros/indigo
     export ROS_DISTRO=indigo
+    export ROS_PACKAGE_PATH=/opt/ros/indigo/share
     export PATH=$PATH:/opt/ros/indigo/bin
     export LD_LIBRARY_PATH=/opt/ros/indigo/lib
     export PYTHONPATH=/opt/ros/indigo/lib/python2.7/site-packages

recipes-ros/ros-comm/roslaunch/roscore-default

 ROS_ROOT=/opt/ros/indigo/
 ROS_DISTRO=indigo
+ROS_PACKAGE_PATH=/opt/ros/indigo/share
 ROS_PORT=11311
 ROS_MASTER_URI=http://localhost:11311
 CMAKE_PREFIX_PATH=/opt/ros/indigo/