Add dogapi.now helper method

lib/index.js

@@ -31,8 +31,23 @@ function initialize(options){
     }
 };
 
+/*section: dogapi
+ *comment: get the current POSIX timestamp
+ *example: |
+ *  ```javascript
+ *  var dogapi = require("dogapi");
+ *  dogapi.now();
+ *  // this is the same as
+ *  parseInt(new Date().getTime() / 1000);
+ *  ```
+ */
+function now(){
+    return parseInt(new Date().getTime() / 1000);
+};
+
 module.exports.client = require("./client"),
 module.exports.initialize = initialize;
+module.exports.now = now;
 module.exports.OK = 0;
 module.exports.WARNING = 1;
 module.exports.CRITICAL = 2;