Organize and refactor LGConstants

* The LGConstants.h is now divided into categories. 
* All of the constants are now prefixed with kLG to make lookup during code completion easier.  
* The notification strings are more consistently named to kLGNotification...   

* How the notification is built in LGTestPort during 
```- (void)portTestDidCompletedWithSuccess:(BOOL )success``` 
  was reworked a touch for consistency

* How the notification is built  in LGEmailer during  
```- (void)sendEmailNotification:(NSString *)subject message:(NSString *)message```
 was reworked as well