Updates/fixes to NTSL

- Fixed NTSL division
  - Added new NTSL math functions
  - Added changelog information

code/modules/scripting/Interpreter/Evaluation.dm

@@ -134,7 +134,7 @@
 			else if(isobject(b) && !isobject(a))
 				RaiseError(new/runtimeError/TypeMismatch("/", a, b))
 				return null
-			if(b==0)
+			if(b==0 || b==null)
 				RaiseError(new/runtimeError/DivisionByZero())
 				return null
 			return a/b
@@ -166,4 +166,4 @@
 	//Unary//
 		Minus(a)						return -a
 		LogicalNot(a)				return !a
-		BitwiseNot(a)				return ~a
+		BitwiseNot(a)				return ~a