3.0.0 release

This release includes several security and performance enhancements, along with initial support for responsive images introduced in WordPress 4.4:

Security: fixes a bug that could allow unauthorized deletion of remotely-stored media.
Security: validate, sanitize, and escape (allthethings).
Security: use https:// URLs by default, and warn if an insecure CNAME is configured.
Security: introduce permissions checks for specific actions within the plugin.
L10N/I18N: Round 1 of preparing strings for translation.
UI: Editor button more closely matches the WordPress Admin UI.
Add srcset to images added through the Media Library when Azure is the default media handler. (Props @patricknami).

Upgrade Notice

This release features several security fixes and enhancements.
It is highly recommended that all users upgrade immediately.