use aoc crate for common stuff

aoc2019/Cargo.toml

@@ -7,3 +7,5 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+
+aoc = { path = "../aoc" }

aoc2019/src/day01.rs

@@ -1,4 +1,4 @@
-use super::Result;
+use aoc::Result;
 
 const INPUT: &str = include_str!("../input/day01.txt");