use es5 builtins like Object.keys and Date.now

this is expected to be used in Node.js
any browser beyond IE8 also supports these functions
someone wanting to use it in IE8 can bring in a polyfill
(style) if cond return true => return cond
Merge pull request #6 from omsmith/es5

use es5 builtins like Object.keys and Date.now
Merge pull request #7 from omsmith/style

(style) if cond return true => return cond
assume nodejs and provide browser build with browserify
parse url params using url module
use url module to build targetUrl