Optimize timestamp retrieval for modern browsers with backwards compatibility 

...ilable in all modern browsers, with backwards compatable option for IE < 9

http://jsperf.com/js-timestamp-retrieval-options

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Date/now
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Date/getTime
![Screen shot 2013-03-26 at 12 20 10 PM](https://f.cloud.github.com/assets/467885/303926/1b8d9aca-9631-11e2-831a-48cc3b8635a8.png)