fix warnings; fix small bug in Bullet; fix impossible prereqs

rules.ini

@@ -543,10 +543,9 @@ Armor=none
 TechLevel=2
 Sight=4
 Speed=3
-Owner=allies
+Owner=allies,soviet
 Cost=300
 Points=10
-DoubleOwned=yes
 
 ; Flamethrower
 [E4]
@@ -602,7 +601,7 @@ Infiltrate=yes
 
 ; Tanya
 [E7]
-Prerequisite=atek
+Prerequisite=atek,stek
 Primary=Colt45
 Secondary=Colt45
 Strength=100
@@ -615,7 +614,6 @@ Cost=1200
 Points=25
 Infiltrate=yes
 C4=yes
-DoubleOwned=yes
 
 ; field medic
 [MEDI]