Day 1 part 2

I didn't realize there was a part two before.

src/main.rs

@@ -3,7 +3,8 @@ mod day2;
 
 fn main() {
     println!("Day 1:");
-    println!("{}", day1::solve().unwrap());
+    println!("{}", day1::solve_part1().unwrap());
+    println!("{}", day1::solve_part2().unwrap().unwrap());
     println!("Day 2:");
     println!("{}", day2::solve_part1().unwrap());
     println!("{}", day2::solve_part2().unwrap().unwrap());