Factorio: add option "Tech Cost Distribution" (#1404)

* Factorio: add option "Tech Cost Distribution"

* TextClient: None out game on disconnect

* TextClient: disconnect is async

worlds/factorio/Options.py

@@ -61,6 +61,19 @@ class MaxTechCost(TechCost):
     default = 500
 
 
+class TechCostDistribution(Choice):
+    """Random distribution of costs of the Science Packs.
+    Even: any number between min and max is equally likely.
+    Low: low costs, near the minimum, are more likely.
+    Middle: medium costs, near the average, are more likely.
+    High: high costs, near the maximum, are more likely."""
+    display_name = "Tech Cost Distribution"
+    option_even = 0
+    option_low = 1
+    option_middle = 2
+    option_high = 3
+
+
 class TechCostMix(Range):
     """Percent chance that a preceding Science Pack is also required.
     Chance is rolled per preceding pack."""
@@ -379,6 +392,7 @@ factorio_options: typing.Dict[str, type(Option)] = {
     "tech_tree_layout": TechTreeLayout,
     "min_tech_cost": MinTechCost,
     "max_tech_cost": MaxTechCost,
+    "tech_cost_distribution": TechCostDistribution,
     "tech_cost_mix": TechCostMix,
     "ramping_tech_costs": RampingTechCosts,
     "silo": Silo,