v3.0.0-alpha.2

Changes

• add support for computed metadata
• add onRemoved guard
• wait for component element to be removed from the DOM before removing metadata to prevent flash during page transitions

uses a MutationObserver, might need a polyfill but afaik any browser supporting Proxy also supports MutationObserver

• some code cleanup
• show active metadata in vue-router example
• improved styling a bit of vue-router example