Longer building tiers

[Adam the Waster]

Sense the game seems to slow progression down I think they should do the same for buildings. The current game is 

Wood

Stone

Concrete 

Steel.

Way to fast and cheap! Imo

It should be

Wood

Stone

Scrap/raw iron

Concrete 

Iron reinforced Concrete 

Steel 

-Gives more uses for iron and iron bars

-slows progression down

-adds more resource management