Refactor the bigger plugins/files #83
Description
#16 is actually a part of this. Some of the big plugins (like Expo, Cube, and Switcher) have accumulated a lot of cruft over time, being ported over from the Xlib -> WLC -> libweston -> wlroots and have also gradually added new features. As a result they are spaghetti code, and must become better so that they are maintainable and bugs in them can be fixed.
Not to mention render-manager.cpp, where everything is just a big mess (but works TM)