Two truck-dumpsters simultaneously active and landfill working

@bballtwenty8 
Working simultaneous trucks, two paths of A star not getting displayed, 
Landfill tile getting overlapped by path "*" when Landfill is selected.

@noahdela 
Updated the truck code with the fuel_filled as global? I did that, you forgot to push.

Let's merge this after we test it and then only two things remain:
1. Update truck's trash levels
2. Update truck's status

They will be able to start working again.
Thanks,