- Rename the feature to "serialization"
- Expand the commentary in README.md a bit
- Add docstrings to the two `PersistentConfig::open()` methods
- Single-line style in the `extern crate` directives

When linking statically on musl targets, this function clashes with a symbol
in OpenSSL. So just rename it.

- Don't bother with the Docker shell scripts, which were one-liners
- docker/x86_musl => dist/docker/x86-alpine-linux-musl
- The rename of AES_cbc_encrypt is now permanently applied
- Run the test suite inside the static container
- Add copyright/license headers
- Move the pkg-config-rs patching script to the specific Docker directory
- Add Cargo.toml note about tracking the correct version of pkg-config.rs