Release v1.8.0

This is the first Immersive Railroading release to be fully dependent on a standalone UniversalModCore!

The majority of the work in this release was towards that support, but many bugs were fixed along the way, and a few new features were added.

• New multiblock models from Tovlyn
• Updated PRR stock from Legend
• Support for multiple tenders behind a steam locomotive
• Improved "invalid block" red overlay
• Right clicking with the golden spike opens up the track GUI and allows placement
• Right clicking on options in the GUI now goes to the "previous" item in the list
• Floating track is now detected properly (instead of breaking a lot of the time erroneously)
• Fix #729 (slightly different driver wheel sizes in a set)
• Villager payout has been fixed
• And lots more!