Image picker support

[RSully]

This branch is a testing ground for adding custom-image support as suggested in #29.

[RSully]

This should probably be in the background

[RSully]

This is pretty broken right now given the "state" concept we implemented.

[dsmurfin]

I can see why the new state stuff has broken this now I've had a look through the code. I reckon this would be quite a useful addition if it can be made to work with the new code.

[RSully]

Yeah I haven't lost hope for this yet.

A few solutions come to mind:

• New state stuff just has to go
• Heavy refactoring with if/else for state vs image.
• State could be refactored into different state types:
  • HSV state
  • Live state (used for custom images, and useful for debugging)

/ping @unixpickle

[dsmurfin]

I guess the cleanest option is potentially no.3. That keeps the logic in the same class etc and should result in less changes to RSColorPickerView

[unixpickle]

If we made a state base class and then subclassed it for HSV and Live states that would possibly work. I'll look into it when I'm free.

[RSully]

Even an interface/protocol might do the job. Edit: abstract/base class is probably better, as suggested.