Feature: Read Qrcode images

Hi, thanks for creating this, I find your solution far more elegant than the very few alternatives.  I've made a few changes for myself, so I'm creating this pull request if you find this feature useful.

#### Ability to drag a QR code image from another Chrome window or local file system

When dragging a QR code image over, the code will read both the secret key as well as the account name and fill those in. 

These changes are using a minified version of the [jsqrcode](https://github.com/LazarSoft/jsqrcode) library.   

#### Had to reindent the HTML file for readability and making it easier to work with

I noticed a lot of whitespace removal in the HTML/CSS.  I'm just commenting that it'd be easier to work with if these source files are unminified, you could probably use something like [grunt](https://github.com/gruntjs/grunt-contrib-uglify) or [hashcat](https://npmjs.org/package/hashcat) to 'build' the minified CSS and JS files if you need it. On the other hand, this is a local web app which will run on the user's computer, maybe minifying isn't necessary?  I'm just thinking in terms of future work and contributions.

#### Jetbrains files added to .gitignore

Noticed you had Eclipse and Visual Studio, I've added Jetbrains .idea folder (IntelilJ, WebStorm, etc) in there so that your code should now work across all the major IDEs.



#### Screenshots

After dragging a QR code image over:

![screenshot from 2014-02-01 11 17 54](https://f.cloud.github.com/assets/746276/2057486/bee60530-8b32-11e3-8682-9cc27951412b.png)

Not filled in:

![image](https://f.cloud.github.com/assets/746276/2057499/d20dd1dc-8b33-11e3-97dc-56e3a6c74d0f.png)