Rockbox

The following code contains low-level primitives needed to interact with the X5 remote LCD.
- It has nothing to do with buttons (ADC driver already handles them)
- It's not tested since I don't have a remote. I didn't even compile it so it might have some syntax errors.

First, this should be converted to a plugin and tested - I added a sample image and a drawing function so it's rather easy.

Then, the whole high level LCD code (frame buffer, line drawing, ...) should be duplicated and interfaced with this.