bench: split to separate package

Unfortunately cargo doesn't allow optional dev dependencies (see
rust-lang/cargo#1596) so this is the workaround.

Previously, running `cargo test` triggered the build of all dev
dependencies, including criterion, which in turn pulls in a lot of
stuff. Running tests should be faster, hence this change.

aoc2019/Cargo.toml

@@ -6,24 +6,13 @@ 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" }
 anyhow = "1.0"
 
 [lib]
 path = "src/lib.rs"
-bench = false
 
 [[bin]]
 name = "aoc2019"
 path = "src/main.rs"
-bench = false
-
-[[bench]]
-name = "bench"
-harness = false

aoc2019/aoc2019_bench/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "aoc2019_bench"
+version = "0.1.0"
+authors = ["Antoine Martin <antoine97.martin@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+aoc2019 = { path = "../" }
+
+[dev-dependencies]
+criterion = "0.3"
+
+[[bench]]
+name = "aoc2019_bench"
+harness = false