Forage Harvester Straw Pickup

Adds in the ability to pickup straw from fields that generate straw from
the crop, to all basegame forage pickup headers.
All modified headers have color selection, slight speed increase, and slight working width increase.
Since the Forage Harvester is chopping the straw, you will also get a slight 10% increase in straw.
Headers:
- Claas PICKUP 300 +
- Kemper 3003 +
- John Deere Header 639 +
- Krone EasyFlow 300 S +
Headers cost $1 more than basegame
License: CC0 1.0 Universal