add changelog; improve docs (#35)

CHANGELOG.md

@@ -0,0 +1,34 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- `SmlReader` type that provides an API for reading, decoding and parsing SML messages from several input sources.
+- CI: Checks for SemVer violations
+- Implement `std::error::Error` for all error types
+
+### Changed
+
+- CI script cleanup
+- Changed `tests/libsml-testing` from submodule to subtree
+
+### Deprecated
+
+### Removed
+
+### Fixed
+
+### Security
+
+### Other
+
+- Updated maintenance badge for 2024
+- Updated hex-literal to 0.4.1
+
+## 0.3.0 - 2023-03-24

src/lib.rs

@@ -3,10 +3,10 @@
 //! Modern German power meters periodically send SML-encoded data via an optical interface.
 //! The main use-case of this library is to decode that data.
 //!
-//! See the `transport` module for encoding / decoding the SML transport protocol v1 and the
-//! `parser` module for parsing decoded data into SML data structures.
+//! See the [`transport`] module for encoding / decoding the SML transport protocol v1 and the
+//! [`parser`] module for parsing decoded data into SML data structures.
 //!
-//! Complete examples of how to use the library can be found on github in the `exmples` folder.
+//! Complete examples of how to use the library can be found on github in the [`examples`](https://github.com/felixwrt/sml-rs/tree/main/examples) folder.
 //!
 //! # Feature flags
 //! - **`std`** (default) — Remove this feature to make the library `no_std` compatible.