Update Bounding Box constructor to allow passing coordinate parameter…

…s in an object.

Updated constructor is backwards compatible, still allows users to call it with coordinates as individual parameters.  Main bounding box tests run for boxes constructed using both methods.

Resolves: excaliburjs#1151.

src/engine/Collision/BoundingBox.ts

@@ -6,17 +6,44 @@ import { Color } from '../Drawing/Color';
 import { obsolete } from '../Util/Decorators';
 import { Side } from './Side';
 
+export interface BoundingBoxOptions {
+  left: number;
+  right: number;
+  top: number;
+  bottom: number;
+}
+
 /**
  * Axis Aligned collision primitive for Excalibur.
  */
 export class BoundingBox {
+  public top: number;
+  public right: number;
+  public bottom: number;
+  public left: number;
+
   /**
-   * @param left    x coordinate of the left edge
+   * Constructor allows passing of either an object with all coordinate components,
+   * or the coordinate components passed separately.
+   * @param leftOrOptions    Either x coordinate of the left edge or an options object
+   * containing the four coordinate components.
    * @param top     y coordinate of the top edge
    * @param right   x coordinate of the right edge
    * @param bottom  y coordinate of the bottom edge
    */
-  constructor(public left: number = 0, public top: number = 0, public right: number = 0, public bottom: number = 0) {}
+  constructor(leftOrOptions: number | BoundingBoxOptions = 0, top: number = 0, right: number = 0, bottom: number = 0) {
+    if (typeof leftOrOptions === 'object') {
+      this.left = leftOrOptions.left;
+      this.top = leftOrOptions.top;
+      this.right = leftOrOptions.right;
+      this.bottom = leftOrOptions.bottom;
+    } else if (typeof leftOrOptions === 'number') {
+      this.left = leftOrOptions;
+      this.top = top;
+      this.right = right;
+      this.bottom = bottom;
+    }
+  }
 
   /**
    * Given bounding box A & B, returns the side relative to A when intersection is performed.