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 15 48 PM](https://f.cloud.github.com/assets/467885/303901/75c5697e-9630-11e2-93c3-9bacf343779c.png)