Add snapshot git alias

Alias for creating a copy of your current working directory (dirty or not) and adding it to the stash then applying it again.

* stash - creates a message with the time of snapshot, and stashes
* apply - returns you back to where you were at

Use case would be to create a quick snapshot then do some **exploratory** coding.  When you are done you can revert back to the snapshot in the stash list, or you can go with the changes.

Credit: [here](http://blog.apiaxle.com/post/handy-git-tips-to-stop-you-getting-fired/)