Implements switching Pokemon and fleeing from battle

PkmnLib.Dynamic/Libraries/MiscLibrary.cs

@@ -19,4 +19,6 @@ public interface IMiscLibrary
     /// Gets the current time of day for the battle.
     /// </summary>
     TimeOfDay GetTimeOfDay();
+
+    bool CanFlee(IBattle battle, IFleeChoice fleeChoice);
 }