Not all templates are being detected

[calebsmith]

I think the exit on first success behavior in the line_stream.py function is incorrect or something. There are several paths that aren't getting picked up.

Needs tests.

[calebsmith]

I think I've found the source of this bug, though my attempts at a quick fix aren't working. The logic around when a template gets added to the set of root node ids is wrong, and many root level templates that are not extended by anything are being excluded. However, simply adding them creates a lot of noise that also seems incorrect or at least wrongly grouped. In other words, we should likely group a collection of "top level" templates that belong to a given app and directory even if they are all independent.

[calebsmith]

This no longer seems as crticial as we thought. All templates that extend or are extended are included. We can use a separate interface for other templates, maybe?