Implement basic move evaluation

It ain't much but it's honest work

rs/src/ui.rs

@@ -258,8 +258,8 @@ impl Ui {
                         format!("Couldn't parse color code {}", color_char)
                     })?,
                 ) {
-                    Some((source, target)) => {
-                        Ok(format!("{},{}", source, target))
+                    Some(move_) => {
+                        Ok(format!("{},{}", move_.source, move_.target))
                     }
                     None => {
                         Err(format!("No move possible for {}", color_char))