Add materializations dirs to include paths for pg/redshift
## Issue

### Issue description
The 0.14.0-a1 pypi distribution of dbt does not include specific macro directories in its `package_data` list. As a result, dbt installed via pip from pypi does not ship with materialization overrides for archival. This manifests as a `merge` statement running for snapshot jobs on pg/redshift projects.

- [package_data](https://github.com/fishtown-analytics/dbt/blob/dev/wilt-chamberlain/plugins/postgres/setup.py#L24-L29)
- unincluded macros:
  - [postgres](https://github.com/fishtown-analytics/dbt/tree/dev/wilt-chamberlain/plugins/postgres/dbt/include/postgres/macros/materializations)
  - [redshift](https://github.com/fishtown-analytics/dbt/tree/dev/wilt-chamberlain/plugins/redshift/dbt/include/redshift/macros/materializations)

We should:
1. include these macro directories in `setup.py` (is there anywhere else to add them?)
2. figure out if there's a good way to keep these things synchronized, or understand if they've fallen out of sync. This works great in development, but only fails once the release is cut on pypi. Is there a way for us to find this earlier?

### Results
dbt used the default snapshot materialization (using a `merge`) and not the pg/redshift-specific implementation provided in the respective plugins.

### System information
The output of `dbt --version`:
```
0.14.0-a1
```

The operating system you're running on:

The python version you're using (probably the output of `python --version`)

### Steps to reproduce
```
pip install dbt
dbt snapshot # on redshift
```
diff --git a/plugins/postgres/setup.py b/plugins/postgres/setup.py
index 3f19b0d9d..d6d9331bb 100644
--- a/plugins/postgres/setup.py
+++ b/plugins/postgres/setup.py
@@ -25,6 +25,7 @@ setup(
         'dbt': [
             'include/postgres/dbt_project.yml',
             'include/postgres/macros/*.sql',
+            'include/postgres/macros/**/*.sql',
         ]
     },
     install_requires=[
diff --git a/plugins/redshift/setup.py b/plugins/redshift/setup.py
index c32fd0e78..17f05a82c 100644
--- a/plugins/redshift/setup.py
+++ b/plugins/redshift/setup.py
@@ -25,6 +25,7 @@ setup(
         'dbt': [
             'include/redshift/dbt_project.yml',
             'include/redshift/macros/*.sql',
+            'include/redshift/macros/**/*.sql',
         ]
     },
     install_requires=[
['plugins/postgres/setup.py', 'plugins/redshift/setup.py']