Add support for images

[drkarl]

Support to include images on the notes, drag and drop an image and paste an image on the clipboard. That would be awesome

[grena]

👍 it could be really nice.

[wbrbr]

You can insert an image like this: ![Image](http://path/to/image)
Example: http://gruik.io/view/426
Drag-and-drop would be nice, I'm gonna try to implement it :)