Nested templates not resolving

**I'm submitting a bug report**

* **Library Version:**
1.0.7

**Please tell us about your environment:**
* **Operating System:**
Windows 10

* **Node Version:**
4.6.0

* **NPM Version:**
3.10.9

* **JSPM OR Webpack AND Version**
webpack 2.1.0-beta.22
* **Browser:**
all

* **Language:**
TypeScript 2.0.9

**Current behavior:**
As described [here](http://stackoverflow.com/questions/40536509/aurelia-nested-template-replace?noredirect=1#comment68338108_40536509) nested templates do not resolve as expected. Shortcut to gist: [here](https://gist.run/?id=a52a0c17d0f7bae22b9ea1987ddc5583)

**Expected/desired behavior:**
If a template has a template both should be resolved.

* **What is the motivation / use case for changing the behavior?**
While the templating is nice and easy to use restricting templates to a single resolution (i.e. only 1 level of templating can be resolved) will limit the extensibility of plugins. It also goes against DRY principles as you'd have to recreate the entire template if you only wanted to change a small part. In the gist above you can see the unfortunate design pattern needed to append the grid's data with bad-app.

Reproduce the nested-template case from the linked Stack Overflow report and gist using the reported Aurelia, webpack, Node, and TypeScript versions. Trace the template-resolution entry point, then verify that a template containing another template resolves both levels and that existing template behavior remains intact.

Written by the indexing model from the issue text.