[board] A couple small changes to support the explorer crate

- DiagramFormatter::new
- Make board::position public

board/src/lib.rs

@@ -3,7 +3,7 @@
 mod bitboard;
 mod moves;
 pub mod piece;
-mod position;
+pub mod position;
 mod square;
 
 #[cfg(test)]

board/src/position/diagram_formatter.rs

@@ -6,6 +6,12 @@ use std::fmt::Write;
 
 pub struct DiagramFormatter<'a>(&'a Position);
 
+impl<'a> DiagramFormatter<'a> {
+    pub fn new(position: &'a Position) -> DiagramFormatter {
+        DiagramFormatter(position)
+    }
+}
+
 impl<'a> fmt::Display for DiagramFormatter<'a> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut output = String::new();