Per application color saturation support (#21)

* Initial implementation without fullscreen support

* Limit saturation to 2

* Fixed saturation not working for fullscreen applications like CSGO

* Fixed saturation ignoring border radius

* Updated README and sway.5 man page

* Rebased from Master

* Added command to README

* Fixed nitpicks

README.md

@@ -5,13 +5,17 @@
 Sway is an incredible window manager, and certainly one of the most well established wayland window managers. However, it is restricted to only include the functionality that existed in i3. This fork ditches the simple wlr_renderer, and replaces it with our fx_renderer, capable of rendering with fancy GLES2 effects. This, along with a couple of minor changes, expands sway's featureset to include the following:
 
 + **Anti-aliased rounded corners, borders, and titlebars**
++ **Per application saturation control**: Allows the user to set the saturation (Digital Vibrance) for specific applications. Great for some FPS games!
 + **Scratchpad treated as minimize**: Allows docks, or panels with a taskbar, to correctly interpret minimize / unminimize requests ([thanks to LCBCrion](https://github.com/swaywm/sway/issues/6457))
 + **Add a nix flake to the repo**: Allows nixos users to easily contribute to and test this project
 
 ## New Configuration Options
+
 + Corner radius: `corner_radius <val>`
++ Application saturation: `for_window [CRITERIA HERE] saturation <set|plus|minus> <val 0.0 <-> 2.0>`
 
 ## Roadmap
+
 + fade in / out animations
 + window movement animations
 + drop shadows