Modernize Tunnel Generation Code

[PersonTheCat]

While it is generally my preference to maintain backward compatibility in some way between versions, the tunnel generation algorithm used by Cave Generator is one of the mod's oldest features. And it shows.

We are due for a complete rewrite of the algorithm from scratch. This includes all of the fields and settings used by tunnels objects. One of the biggest problems with the current implementation is that it was specifically designed to avoid breaking seeds when coming from the vanilla generator, but we have long since broken this feature. It is time to move on and design a new implementation of the tunnel generator which bypasses all of the cumbersome and quirky features from Cave Generator 1.0.

Priority: medium

This should be completed prior to CG 2.0, but ideally prior to the initial 1.16 port.

Affected Areas:

• TunnelGenerator - partially rewritten
• ScalableFloat - removed or overhauled
• TunnelPathInfo - removed or overhauled
• TunnelSettings - potentially very different settings from before