REFACTOR use MetaComponents() method allowing for better extensibility

[muskie9]

resolves #59

This is a fairly major change to how the tags are built. I've updated the existing tests to match using the MetaComponents() method and things appear to be generating as expected.

One thing I did not take into account with this update is if there is a desire for additional logic surrounding the handling of the canonical tag for things like Virtual Page, or if a canonical already exists from some other extension. If this module's extension is loaded last, it will simply overwrite any canonical in the MetaComponents. That being said, any module using the MetaTags() method, and setting a canonical could result in two canonical tags being generated.

Open to feedback on any/all of this and am happy to update where needed.

[oddnoc]

Could you rebase your branch on develop? Thanks!

[sunnysideup]

could this be actioned @oddnoc ?