feature: 'pos' struct

It would be useful to create a standard that represents the position of a sprite. I use this extensively in some of my code and I think it would be a useful struct to be standardized. this way, a standard library for the pos struct can be made.

The pos struct consists of 4 attributes:
- x (position)
- y (position)
- s(ize)
- d(irection)
