Update instructions to ubuntu-18.04.

doc/instructions.md

-## Binary installation on ubuntu-16.04 64 bit with ros-kinetic
+## Binary installation on ubuntu-18.04 64 bit with ros-melodic
 
-To install all the packages on ubuntu 16.04 LTS 64 bit, you should do the following steps:
+To install all the packages on ubuntu 18.04 LTS 64 bit, you should do the following steps:
 
-  1. install ROS-kinetic: follow steps 1.1 to 1.3 of [the ROS installation website.](http://wiki.ros.org/kinetic/Installation/Ubuntu).
+  1. install ROS-melodic: follow steps 1.1 to 1.3 of [the ROS installation website.](http://wiki.ros.org/melodic/Installation/Ubuntu).
 
   2. install robotpkg: follow [the robotpkg installation website](http://robotpkg.openrobots.org/debian.html).
 
   3. install HPP: `sudo apt-get install robotpkg-hpp-tutorial robotpkg-osg-dae`
 
   4. install (optionnal) extra packages for demonstrations:
-     `sudo apt-get install robotpkg-hpp-tutorial robotpkg-osg-dae ros-kinetic-pr2-description robotpkg-hpp-environments robotpkg-hpp-universal-robot robotpkg-romeo-description robotpkg-ros-baxter-common`
+     `sudo apt-get install robotpkg-hpp-tutorial robotpkg-osg-dae ros-melodic-pr2-description robotpkg-hpp-environments robotpkg-hpp-universal-robot robotpkg-romeo-description robotpkg-ros-baxter-common`
 
   4. setup your environment variables by adding the following lines to your `.bashrc`:
 
     ```bash
-    source /opt/ros/kinetic/setup.bash
+    source /opt/ros/melodic/setup.bash
 
     export PATH=/opt/openrobots/bin${!PATH:-:}${PATH}
     export LD_LIBRARY_PATH=/opt/openrobots/lib${!LD_LIBRARY_PATH:-:}${LD_LIBRARY_PATH}
@@ -28,11 +28,11 @@ To install all the packages on ubuntu 16.04 LTS 64 bit, you should do the follow
   5. open `/opt/openrobots/share/doc/hpp-doc/index.html` in a web brower and you
   will have access to the documentation of most packages.
 
-## Source installation on ubuntu-16.04 64 bit with ros-kinetic
+## Source installation on ubuntu-18.04 64 bit with ros-melodic
 
-To install all the packages on ubuntu 16.04 LTS 64 bit, you should do the following steps:
+To install all the packages on ubuntu 18.04 LTS 64 bit, you should do the following steps:
 
-  1. install ROS-kinetic: follow steps 1.1 to 1.3 of [the ROS installation website.](http://wiki.ros.org/kinetic/Installation/Ubuntu).
+  1. install ROS-melodic: follow steps 1.1 to 1.3 of [the ROS installation website.](http://wiki.ros.org/melodic/Installation/Ubuntu).
 
   2. install robotpkg: follow [the robotpkg installation website](http://robotpkg.openrobots.org/debian.html).
 
@@ -50,12 +50,14 @@ To install all the packages on ubuntu 16.04 LTS 64 bit, you should do the follow
       robotpkg-roboptim-core \
       robotpkg-roboptim-trajectory \
       robotpkg-romeo-description \
-      ros-kinetic-xacro \
+      robotpkg-ros-baxter-common \
+      robotpkg-ros-universal-robot \
+      ros-melodic-xacro \
       libccd-dev \
-      ros-kinetic-octomap \
-      ros-kinetic-resource-retriever \
-      ros-kinetic-srdfdom \
-      ros-kinetic-pr2-description \
+      ros-melodic-octomap \
+      ros-melodic-resource-retriever \
+      ros-melodic-srdfdom \
+      ros-melodic-pr2-description \
       git \
       libomniorb4-dev \
       omniorb-nameserver \
@@ -88,7 +90,7 @@ To install all the packages on ubuntu 16.04 LTS 64 bit, you should do the follow
   5. Copy Config and Makefile
 
     ```bash
-    wget -O $DEVEL_HPP_DIR/config.sh https://raw.githubusercontent.com/humanoid-path-planner/hpp-doc/devel/doc/config/ubuntu-16.04-kinetic.sh
+    wget -O $DEVEL_HPP_DIR/config.sh https://raw.githubusercontent.com/humanoid-path-planner/hpp-doc/devel/doc/config/ubuntu-18.04-melodic.sh
     wget -O $DEVEL_HPP_DIR/src/Makefile https://raw.githubusercontent.com/humanoid-path-planner/hpp-doc/devel/doc/Makefile
     ```