chore(math): initialize pallas-math crate (#474)

pallas-math/src/lib.rs

@@ -0,0 +1 @@
+pub mod math;

pallas-math/src/math.rs

@@ -0,0 +1,17 @@
+/*!
+# Cardano Math functions
+*/
+
+pub fn add(a: i32, b: i32) -> i32 {
+    a + b
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_add() {
+        assert_eq!(add(1, 2), 3);
+    }
+}