Updated readme, naming, exports, and fixes to antipattern behavior

• Plugin name finally reflects... the actual name of the plugin
• Exported function (though unlikely to have been ever used in anyone's config as there is no config) is now appropriately named, and hypothetically could break some oddball configurations, but as this is an extreme edge-case, the version bump will remain minor
• Fix to antipattern detection, will now correctly interpret positions when extensions are outbound from media queries, or default to not warning (when it can't detect positions)
• Readme updated for consistency, and grammatical correctness by everyone's favorite @kswedberg