* IV: Setting up cmakelists and package.xml for ROS2.

* IV: Renaming and reorganizing files for ROS2 port.

* IV: Ported most tools. Working on GUI apps.

* IV: Continuing port.

* More porting.

* Fixing compilation errors.

* Fixing install location. Removing unused parameter.

* Images can be viewed!

* imshow is broken but everything else works better.

* Most stuff works!

* Fixing topic lookup in stereo_view.

* Making extract_images into a component.

* Making image_saver into a component.

* Making stereo_view into a component.

* Making video_recorder into a component.

* Updating copyrights and adding dual-licensing.

* image_view: Reorganizing constructors. Squashing bugs.

* image_view: Removing request_start_end parameter.

* image_view: Adding parameter change callback.

* image_view: Window now reliably closes with X and shuts down node.