Add a Buffer::present_with_damage() method

Supported on Wayland, X11, and Win32.

Fixes https://github.com/rust-windowing/softbuffer/issues/39.

try_for_each

src/cg.rs

@@ -1,4 +1,4 @@
-use crate::SoftBufferError;
+use crate::{Rect, SoftBufferError};
 use core_graphics::base::{
     kCGBitmapByteOrder32Little, kCGImageAlphaNoneSkipFirst, kCGRenderingIntentDefault,
 };
@@ -119,6 +119,10 @@ impl<'a> BufferImpl<'a> {
 
         Ok(())
     }
+
+    pub fn present_with_damage(self, _damage: &[Rect]) -> Result<(), SoftBufferError> {
+        self.present()
+    }
 }
 
 impl Drop for CGImpl {