Updated to tag manager 3.0.0

This is the latest version of tag manager. They changed the name from bootstrap-tagmanager to tagmanager. The JS and CSS also changed, so if you're following semver might need a bigger change that 0.0.3.

https://github.com/max-favilli/tagmanager/releases/tag/v3.0.0
http://welldonethings.com/tags/manager/v3

Thanks!