add Indian assets (#800)

* War Elephant icon

* Mughal Fort icon

* credits for Indian unique icons

* bonuses for Castle apply to Mughal Fort too

* getCityHappiness() complies with the Indian unique

* getCityHappiness() complies with the Indian

missing bracket 🙄

Credits.md

@@ -25,6 +25,7 @@ All the following are from [the Noun Project](https://thenounproject.com) licenc
 * [Fishing Vessel](https://thenounproject.com/term/fishing-vessel/23815/) By Luis Prado for Work Boats
 * [Greek Trireme](https://thenounproject.com/search/?q=ancient%20boat&i=1626303) By Zachary McCune for Trireme
 * [Chariot](https://thenounproject.com/search/?q=Chariot&i=1189930) By Andrew Doane for Chariot Archer
+* [Elephant](https://thenounproject.com/Luis/uploads/?i=14048) By Luis Prado, US for War Elephant
 * [Spear](https://thenounproject.com/search/?q=Spear&i=11432) By Stephen Copinger for Spearman
 * [Greek shield](https://thenounproject.com/search/?q=hoplite&i=440135) for Hoplite
 
@@ -175,6 +176,7 @@ All the following are from [the Noun Project](https://thenounproject.com) licenc
 * [Chichen Itza](https://thenounproject.com/term/chichen-itza/668065/) By Hea Poh Lin
 * [Christian Church](https://thenounproject.com/term/christian-church/1174183/) By Andrejs Kirma for Monastery
 * [Castle](https://thenounproject.com/search/?q=castle&i=390189) By Mint Shirt
+* [Red Fort](https://thenounproject.com/arunabh.jain.0fficial/collection/famous-indian-monuments/?i=2092466), [Gateway of India](https://thenounproject.com/arunabh.jain.0fficial/collection/famous-indian-monuments/?i=2092468) By Arunabh Jain, IN for Mughal Fort
 * [Cambodia](https://thenounproject.com/term/cambodia/1809152/) By Wichai Wi for Angkor Wat
 * [Alhambra](https://thenounproject.com/search/?q=alhambra&i=403759) By parkjisun
 * [Books](https://thenounproject.com/term/books/1140218/) By Abir Alward for Oxford University

core/src/com/unciv/logic/city/CityStats.kt

@@ -176,7 +176,11 @@ class CityStats {
         if(!civInfo.isPlayerCivilization())
             unhappinessModifier *= civInfo.gameInfo.getDifficulty().aiUnhappinessModifier
         
-        newHappinessList ["Cities"] = -3f * unhappinessModifier
+        var unhappinessFromCity=-3f
+        if (civInfo.getNation().unique=="Unhappiness from number of Cities doubled, Unhappiness from number of Citizens halved.") 
+            unhappinessFromCity*=2f//doubled for the Indian
+
+        newHappinessList ["Cities"] = unhappinessFromCity * unhappinessModifier
 
         var unhappinessFromCitizens = cityInfo.population.population.toFloat()
         if (civInfo.policies.isAdopted("Democracy"))
@@ -185,6 +189,8 @@ class CityStats {
             unhappinessFromCitizens *= 0.9f
         if (civInfo.policies.isAdopted("Meritocracy"))
             unhappinessFromCitizens *= 0.95f
+        if (civInfo.getNation().unique=="Unhappiness from number of Cities doubled, Unhappiness from number of Citizens halved.")
+            unhappinessFromCitizens *= 0.5f //halved for the Indian
 
         newHappinessList["Population"] = -unhappinessFromCitizens * unhappinessModifier
 

core/src/com/unciv/models/gamebasics/Building.kt

@@ -151,7 +151,8 @@ class Building : NamedStats(), IConstruction{
             if (adoptedPolicies.contains("Autocracy Complete") && cityStrength > 0)
                 stats.happiness += 1
 
-            if (name == "Castle" && civInfo.getBuildingUniques().contains("+1 happiness, +2 culture and +3 gold from every Castle")){
+            if (hashSetOf("Castle", "Mughal Fort").contains(name) 
+                    && civInfo.getBuildingUniques().contains("+1 happiness, +2 culture and +3 gold from every Castle")){
                 stats.happiness+=1
                 stats.culture+=2
                 stats.gold+=3