message: Javascript bitwise operators coerce to *signed* integers, unlike C.
  Magically, you can coerce back to unsigned by append ">>> 0".
diff: @@ -289,7 +289,7 @@ export class ColorDef {
  /** the color value of this ColorDef as an integer in the form 0xTTBBGGRR (red in the low byte) */
  public get tbgr(): number { return this._tbgr; }
  - public set tbgr(tbgr: number) { this._tbgr = tbgr | 0; }
  + public set tbgr(tbgr: number) { this._tbgr = (tbgr | 0) >>> 0; }
  /** get the value of the color as a number in 0xAABBGGRR format (i.e. red is in low byte). Transparency (0==fully opaque) converted to alpha (0==fully transparent). */
  public getAbgr(): number { scratchUInt32[0] = this._tbgr; scratchBytes[3] = 255 - scratchBytes[3]; return scratchUInt32[0]; }
  