Add Align type

TODO: Commit message body
TODO: Tests

Author: joshlf

Cargo.toml

@@ -49,6 +49,12 @@ default-features = false
 optional = true
 
 [dev-dependencies]
+# WARNING: Struct field byte offset is a problem which has a history of being
+# difficult to solve soundly in Rust. There's no reason to believe that
+# `memoffset` in particular has done anything wrong, but we should still
+# scrutinize it more closely if we ever intend to move this to a non-dev
+# dependency.
+memoffset = "0.6.5"
 rand = "0.6"
 rustversion = "1.0"
 static_assertions = "1.1"