Add-on Capability

[ronalfy]

Ryan pseudo-gave me the go-ahead to write a Reorder Posts add-on that allows sorting by post-type/taxonomy/term.

I need to create an add-on structure that makes sense that way both plugins play nice with eachother.

I'll be creating a separate branch for this feature and merge it in when it makes sense.

[ryanhellyer]

My go-ahead is not required for anything :P

[ronalfy]

Add-on capability is now in the main branch.