Added support for Cordova 2.9

Followed the instructions of Apache Cordova API documentation for iOS plugin development at http://cordova.apache.org/docs/en/2.9.0/guide_plugin-development_index.md.html#Plugin%20Development%20Guide :

-Changed the format of Cordova command in GoogleAnalyticsPlugin.js
-Changed the format of the methods and way of getting parameters in GoogleAnalyticsPlugin.m 
-In GoogleAnalyticsPlugin.h removed the method declarations.