Simply save this as a script in the root folder and run it. This will install the Evernote SDK and all its dependencies in a sub folder named "evernote-sdk".
To actually use it with your Evernote account, you need to create a developer token. You can do that here:
The demo shows a list of all your notebooks and then creates a new note in the default notebook. If you have an image in the clipboard, that image is attached to the note (as a png file).
Unfortunately, the developer token page is not really optimized for iOS, I guess they didn't expect anyone to use it there. :)
It's still possible to copy the token directly from Safari/Chrome. The trick is to double-tap on the token (not touch and hold), and then drag the handles to select the entire thing.
I'd recommend to double-tap on the end of the token, and only drag the handle that marks the beginning of the selection. When you drag the other handle, the selection tends to disappear if you don't drag in a perfect horizontal line.