* : Moved all the Device related class inside a folder name Device
config/app.config.js : added localhost:8080 as callback uri
src/CallbackService.js: Resolved bug of sending payload member inspite of postBody and passing body with event without parsing
src/Device/Device.js : Identation change and renamed private members with _functionName
src/Devices.js : implemented devices class that keeps track of all the Device object
src/Enums.js: Resolved bug of as value 0 is equivalent to false hence checked whether Enum value exists or not
src/Push/Push.js : Indentation changes
Test/Devices.js : added test for Devices.js
Test/Device.js: Modified test function for Device class