Merge pull request #356 from bulwahn/master

minor improvements to documentation and environment variables

README.md

-This is a layer to provide ROS Hydromedusa in an OpenEmbedded Linux system.
+This is a layer to provide ROS Indigo Igloo in an OpenEmbedded Linux system.
 It provides a stable cross-compilation build system for many common ROS packages. 
 Currently, this layer is still under continuous development.
 
@@ -161,6 +161,8 @@ Currently, this layer is still under continuous development.
   to the /etc/hosts file, and set up the environment with
 
     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/