Plugin tutorial: Gazebo starts but not plugin

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I'm doing the Velodyne LiDAR plugin tutorial (http://gazebosim.org/tutorials?cat=gu...), but I can't get Gazebo to recognize the plugin. I have copied the code from steps 2-4 and successfully built it using cmake and make, but when I run the scene using

cd ~/velodyne_plugin/build
gazebo ../velodyne.world

Gazebo just starts the scene without outputting anything to the terminal. I also tried adding the code supposed to spin the joint, as in step 5, with the same result. I even tried removing the plugin library file (libvelodyne_plugin.so) that I built altogether, while still having the line

<plugin name="velodyne_control" filename="libvelodyne_plugin.so"/>

in my .world-file and Gazebo still launches the scene just fine. I also tried adding another model (the Cessna air plane) to the .world-file, and that one appears as it should.

Any ideas?

EDIT: My OS is Ubuntu 16.04, and I run Gazebo version 7.0.0

EDIT2: Using the --verbose tag gives the following output:

~/Developer/Gazebo/velodyne_plugin/build$gazebo ../velodyne.world --verbose
Gazebo multi-robot simulator, version 7.0.0
Copyright (C) 2012-2016 Open Source Robotics Foundation.
Released under the Apache 2 License.
http://gazebosim.org

[Msg] Waiting for master.
Gazebo multi-robot simulator, version 7.0.0
Copyright (C) 2012-2016 Open Source Robotics Foundation.
Released under the Apache 2 License.
http://gazebosim.org

[Msg] Waiting for master.
[Msg] Connected to gazebo master @ http://127.0.0.1:11345
[Msg] Connected to gazebo master @ http://127.0.0.1:11345
[Msg] Publicized address: 192.168.121.123
[Msg] Publicized address: 192.168.121.123
[Err] [Plugin.hh:165] Failed to load plugin libvelodyne_plugin.so: libvelodyne_plugin.so: cannot open shared object file: No such file or directory