Fix missing ngtemplatecache

Without explicit install of laravel-elixir-ngtemplatecache gulp tasks will not find it and fail.

npm 3.5.0
gulp 3.9.0

Author: MattiJarvinen-BA

docs/1-Installation.md

@@ -25,6 +25,7 @@ NPM
 ---
 ```bash
 npm install laravel-elixir-ng-templates@^0.1.2 --save
+npm install laravel-elixir-ngtemplatecache@^0.2.0 --save
 npm install underscore --save
 ```