Adds modular buildings, which are 2/4 identical buildings condensed into one entity. Based on Modular Buildings by staplergun.

Currently double and quad steam turbines and engines are supported. If two are placed together end to end they will be joined into a single entity. If two double versions are together end to end they will join into a quad version. This reduces entity counts and saves UPS. You can not have a single-double-single combine into a quad version, you must deconstruct the double and place the individual ones.

Blueprinted versions are buildable via robot by using the appropriate number of items. Note that even if your robot carrying capacity is smaller than the amount needed, Factorio always allows a single robot to carry enough to construct/deconstruct the buildings.