Add auto_extend option

If set to true, when setting the ANSI property, rather than throwing away
vertically "scrolled" lines, just keep extending the height to accommodate the
new required vertical size (height).

exec/load/graphic.js

@@ -61,6 +61,12 @@ function Graphic(w,h,attr,ch, dw)
 	}
 }
 
+Graphic.prototype.extend = function() {
+	for(var x = 0; x < this.width; x++)
+		this.data[x][this.height] = new this.Cell(this.ch,this.attribute);
+	this.height++;
+}
+
 /*
  * Default to not DoorWay mode, allow it to be overridden per object, or
  * globally.
@@ -392,8 +398,12 @@ Object.defineProperty(Graphic.prototype, "ANSI", {
 				y++;
 			}
 			while(y >= this.height) {
-				this.scroll();
-				y--;
+				if(this.auto_extend === true)
+					this.extend();
+				else {
+					this.scroll();
+					y--;
+				}
 			}
 		}
 	}