util/rational: add Rational

src/util/rational.rs

@@ -0,0 +1,14 @@
+use ffi::*;
+
+#[derive(Eq, PartialEq, Copy, Clone, Debug)]
+pub struct Rational(pub AVRational);
+
+impl Rational {
+	pub fn numerator(&self) -> i32 {
+		self.0.num
+	}
+
+	pub fn denominator(&self) -> i32 {
+		self.0.den
+	}
+}