colcon build --symlink-install broken for catkin packages

[rhaschke]

It looks like colcon build --symlink-install is fundamentally broken for catkin packages. So far, I found the following issues:

• colcon --symlink-install fails to symlink versioned (catkin) libraries #147
• LD_LIBRARY_PATH not correctly set #148
• python-based packages are installed in non-editable mode (essentially ignoring --symlink-install)
  I prepared an example package: https://github.com/rhaschke/test/tree/colcon
  Build with: colcon build --merge-install --symlink-install --event-handler console_direct+

Although being advertized for ROS 1 packages in the docs, the devel-space experience from ROS1 is not yet available. 😞