HAR logger

Implemented resource request log from prerender service. I have created a log/currentDate/ folder in the root path, then a file named phantomId.har will created for a phantom request. Copy the contents of the file and paste it in this url(http://www.softwareishard.com/har/viewer/), you will be able to see the chrome like network tab which shows request time consumption, wait time and request sequence.

It will more useful for people who wants to do application level optimization.