Refactor xcomposite into abstract capture api

Refactor c++ files into c files, more usable

TODO

@@ -13,4 +13,5 @@ Allow recording a region by recording the compositor proxy window / nvfbc window
 Resizing the target window to be smaller than the initial size is buggy. The window texture ends up duplicated in the video.
 Handle frames (especially for applications with rounded client-side decorations, such as gnome applications. They are huge).
 Use nvenc directly, which allows removing the use of cuda.
-Fallback to nvfbc and window tracking if window capture fails.
+Fallback to nvfbc and window tracking if window capture fails.
+Handle xrandr monitor change in nvfbc.