Allow parsing of responses from DELETE requests

[thewheat]

Why?

• Current code just returns null for all DELETE requests
• In PR 241 made an attempt to fix it but found that Tag.delete had an issue with the new code

How?

• So now we check if DELETE response has data if it does proceed to process it as any other normal data
• If there is no data just return null
• Ran through all delete usage and all of them process and parse new code correctly

User.archive(Map<String, String> params)
User.archive(String id)
Contact.delete(String id)
Contact.deleteByUserID(String user_id)
Visitor.delete(Visitor v)
Visitor.delete(String id)
Tag.delete(String id)
Tag.delete(Tag tag) 
Subscription.delete(Subscription subscription)

[choran]

@thewheat I would like to spend a little more time on this one since I think it could impact any delete in the API. I am just not sure at the moment so would like to hold off on this for now.

[thewheat]

@choran Certainly understandable 👍

[choran]

👍