Add package.xml for superbuild.

package.xml

+<package format="2">
+  <name>eiquadprog</name>
+  <version>1.1.3</version>
+  <description>
+    Eiquadprog a QP solver using active sets
+  </description>
+  <maintainer email="ostasse@laas.fr">Olivier Stasse</maintainer>
+  <license>LGPLv3</license>
+
+  <url>git@github.com:stack-of-tasks/eiquadprog.git</url>
+  <author>Gabriele Buondonno</author>
+  <author>Andrea Del Prete</author>
+  <author>Luca Di Gaspero</author>
+  <author>Angelo Furfaro</author>  
+  <author>Benjamin Stephens</author>
+  <author>Gael Guennebaud</author>
+  
+  <build_depend>roscpp</build_depend>
+
+  <exec_depend>roscpp</exec_depend>
+
+  <buildtool_depend>catkin</buildtool_depend>
+
+  <doc_depend>doxygen</doc_depend>
+
+</package>