Adding sender to the protocol methods

The current implementation of iRate does not provide the source in the protocol methods.  

It is typical for delegation messages to contain the source.  See this section on apple's docs.

https://developer.apple.com/library/ios/documentation/general/conceptual/CocoaEncyclopedia/DelegatesandDataSources/DelegatesandDataSources.html#//apple_ref/doc/uid/TP40010810-CH11-SW3

When binding the iRate library to other languages that expect this argument, incorrect assumptions are made and the API appears broken.