Compatibility update for 1.15.* Kaiser.

Updated to reflect changes to the Rt56 air tech tree.

Updated for 1.13 Stella Polaris

Small update to fix UI layout issues in the motorisation research tab.

Hotfix to rebalance Steel/Aluminium Mill IC cost.

This is the 2.0 update which provides compatibility for 1.12 Avalanche.

This update adds the Resource Extractors that are present in the vanilla version of the mod. For the sake of compatibility, Rt56's Steel and Aluminium Mills remain as separate research paths, but have been rebalanced to keep them in line with the general tech progression seen in the vanilla version. Tungsten/Chromium Extractors are on a shared research path.