This PR has a few things to improve the discoverability of Serde support:
Enable all features in the docs.rs build, so the serde module is documented
Remove trailing whitespace in readme (my editor is configured to strip trailing whitespace, so it did this, this is totally optional)
Update the version of bendy in the readme to 0.3
Add a section documenting the basics of serde support, and how to enable it
Add a pointer to the serde module docs in the readme (I'm not sure if this should be added now, since the link will be broken until a new version is released which enables all features for the docs.rs build)
This PR has a few things to improve the discoverability of Serde support: