Update build to ros/groovy

  Install package the same ways as catkin would do without using catkin.
Notify copyright and license.
Export binary installation directory in pkg-config file.
Do not redefine bindir. Let user choose where to install things.
Install executable in pkglibdir.

  pkglibdir is equal to $libdir/$packagename.
  No use to define bindir anymore.
Provide files as argument. Do not try to guess where they are installed

  Modification to comply with groovy policy to install files in a standard way.
Upgrade script to new data structure provided by from_xml_string()

  links is now an array. It seems that it used to be a map.