Make toasterContainer directive use a private scope and add git ignore file

Hi,

Here are two small suggested improvements:

1. Added `scope: true` setting on the `toasterContainer` directive to avoid spreading its scope variables onto the parent scope.  
Otherwise without it, I found that I end up having `config`, `configureTimer`, `toasters`, etc.. on my own scope.
2. Added git ignore file to ignore bower components, npm and some text editor's temp files.

Cheers,

David