Merge branch 'v0.4.x' into uplift-0.4-commits

Cargo.toml

@@ -1,7 +1,12 @@
 [package]
 
 name          = "bytes"
-version       = "0.5.0" # don't forget to update html_root_url
+# When releasing to crates.io:
+# - Update html_root_url.
+# - Update CHANGELOG.md.
+# - Update doc URL.
+# - Create "v0.4.x" git tag.
+version       = "0.5.0"
 license       = "MIT"
 authors       = ["Carl Lerche <[email protected]>"]
 description   = "Types and traits for working with bytes"
@@ -27,6 +32,7 @@ features = ["i128"]
 byteorder = "1.1.0"
 iovec = { git = "https://github.com/carllerche/iovec" }
 serde = { version = "1.0", optional = true }
+either = { version = "1.5", default-features = false, optional = true }
 
 [dev-dependencies]
 serde_test = "1.0"