add benches for 2015 and 2018

aoc2015/Cargo.toml

@@ -6,7 +6,24 @@ edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[dev-dependencies]
+
+criterion = "0.3"
+
 [dependencies]
 
 aoc = { path = "../aoc" }
 md-5 = "0.8"
+
+[lib]
+path = "src/lib.rs"
+bench = false
+
+[[bin]]
+name = "aoc2015"
+path = "src/main.rs"
+bench = false
+
+[[bench]]
+name = "bench"
+harness = false