Combine item related resources into a single one.

[TheLX5]

The less slots they use up, the better.

The sprites part can be done via Extra Bytes and would require reprogramming some parts of the item box and item gfx engines.

The blocks could be condensed in a single asm file quite easily, making the insertion process less painful at the cost of descriptions I guess. This one is quite tricky.

[TheLX5]

Idea for the blocks descriptions: Include an (optional) python script to append the fixed descriptions after GPS runs. I'm already doing this for my hack, so it's matter of thinking a good way to do this.