docs(README): add alternative git clone method

Closes #239

Author: petebacondarwin

README.md

@@ -31,6 +31,14 @@ git clone https://github.com/angular/angular-seed.git
 cd angular-seed
 ```
 
+If you just want to start a new project without the angular-seed commit history then you can do:
+
+```bash
+git clone --depth=1 https://github.com/angular/angular-seed.git <your-project-name>
+```
+
+The `depth=1` tells git to only pull down one commit worth of historical data.
+
 ### Install Dependencies
 
 We have two kinds of dependencies in this project: tools and angular framework code.  The tools help