Update notes for v0.51

Truck City v0.51 has just been released. This is the change log:

• Feature: each factory can be configured to only allow inbound containers from factories in a configurable range

• Balance: all rocket parts are now x2 to x5 slower to manufacture, rocket launchpad is x10 slower. Affected factories: Ammonia Synthesizer, Orbital Fuel Unit, Ammoxidizer, Polymer Carbonizer, BPA Condensation Reactor, Epoxy Polymerizer, Insulation Factory, Rocket Launchpad
• Balance: production time also increased (to a lower degree) for the following factories: Iron foundry, Steel foundry, Rebar foundry, Piping factory, Grinder-magnetizer, Engine Assembly, Copper Foundry, Electromagnetic Coil
• Feature: confetti on victory!

• Improvement: full dependency graph for item production is now a bit clearer
• Balance: initial amount of money increased in tutorial 1
• Improvement: added information on distance to destination in the truck window
• Bugfix: fixed minor glitch where containers in warehouses might get partially obscured by the factory overlay when Alt mode was enabled.
• Bugfix: minor bugfix where the factory overlay for Alt mode was not correctly updated on rocket launchpad deletion
• Bugfix: fixed bug where parking spots may be counted as occupied even when empty
• Improvement: improved translations
• Improvement: efficiency improvements on copy/pasting