0.4.1B - Bug fix and Linux version

This is a small update, fixing a critical bug and adding some minor changes to building sprites.

Apart from that, we released a working Linux version!

Change log for 0.4.1B

Linux
- Included up-to-date build for Linux

Bug fix
- Hovering mouse while placing farm over tiles with 10 in food value no longer crashes the placing farm state

Art
- updated art for Civilisation Center
- updated art for Dwelling
- updated art of Granary

Balance
- Organised Warfare technology now increases military production by 25%, up from 15%