v0.13.0

This release adds UTF-8 support to the EmailField along with other validation tweaks (#1527).

Previously, email addresses containing Unicode characters didn't work at all. Now, domains with Unicode characters are supported out of the box and similar validation on the user part can be explicitly enabled. Additionally, you can enable an optional validation of IP-based domain parts (e.g. "user@[127.0.0.1]"), and you can have a whitelist of otherwise invalid domains (e.g. "root@localhost").