Encapsulate instance variables about the current page in a class

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

• Close this issue

We've got way too much usage of instance variables all over the place for the current state of a page, such as @project, @ref, @repo, @path -- basically everything in ExtractsPath.

I think it would be much cleaner to encapsulate all of these in something like a CurrentPage singleton class.

cc @DouweM @grzesiek