Annotate for Mac - Blank Slate

Continuing to work on this app when I get time.

Here is the first pass at designing the initial state of the app.

As I've mentioned, I generally take screenshots using the OS X system default of command+control+shift+4 which allows me to grab a certain area of the screen or an entire window and save it to the clipboard.

If Annotate detects an image on your clipboard, it will prompt you to use command+v to paste it onto the canvas (this is the quickest workflow for me and the one I focused Annotate on). Eventually it would be nice to see a preview of the clipboard content, but we'll keep it simple for now.