Try to spawn a worker without additional requests

If Blob and URL.createObjectURL we can save a web request and the
additional evaluation of the given code.

Author: Sebmaster

lib/thread.js

@@ -90,8 +90,25 @@
 	};
 
 	Thread.prototype._spawnWorker = function (cb) {
-		var wrk = new Worker(this.options.path);
-		wrk.postMessage(Thread.getWorkerSource(cb));
+		var wrk;
+		if (isNode) {
+			wrk = new Worker(this.options.path);
+			wrk.postMessage(Thread.getWorkerSource(cb));
+		} else {
+			try {
+				var blob = new Blob([Thread.getWorkerSource(cb)], { type: 'text/javascript' });
+				var url = URL.createObjectURL(blob);
+
+				wrk = new Worker(url);
+			} catch (e) {
+				if (this.options.ie10shim) { // blob/url unsupported, cross-origin error
+					worker = new Worker(this.options.path);
+					worker.postMessage(str);
+				} else {
+					throw e;
+				}
+			}
+		}
 
 		return wrk;
 	};