- Remove y coordinate from struct for credits_pics

- Update x coordinates for credits_pics entries
- Reorder credits_pics entries (what even was the previous order lol)
- Add zig zag graphics to credits roll
- Attempt to scale the y positions of credits graphics with the length of the credits roll
- New escape character for credits entries: \2, which centers the text and makes it yellow
- Add support for colored text to V_DrawStringAtFixed