@Extra convention over configuration #188

This was a very good suggestion from someone in the audience at the AndroidAnnotations presentation at Devoxx France

We should use a convention over configuration mechanism for intent extras, and use the field name when no name is provided for the extra. E.g :

@EActivity
public class MyActivity extends Activity {

    // The extra will be named "someExtra", no need to use @Extra("someExtra")
    @Extra
    String someExtra;
}