Changed globbing patterns to support subfolders at any level

Hello, it's me again :smile: 

The globbing pattern used in the scaffolded  Gruntfile.js (```{,*/}``` ) doesn't handle well subdirectories.
It  works well only for files in the root directory or in a first level subdirectory.

This may cause troubles.
An example with the ```watch``` task:
```scripts/controllers/foo.js``` is "watched", but ```scripts/controllers/foodir/foo.js``` is not.

I changed all the ```{,*/}``` in Gruntfile.js with a ```**``` and everything seems to work fine.
More info here: http://gruntjs.com/configuring-tasks#globbing-patterns