Last changes to connection helper before 22 March 2013
Merge pull request #7 from eclements/feature/new-sdk-1.4.6

Last changes to connection helper before 22 March 2013
Retrieval of contact list now gets more than 27 contacts (uses loop).
Amended Authenticate function to only append headers if not already there.
Merge pull request #8 from georgezee/contactlist-improvements

Improved contactlist retrieval
Added new EnqeueMessage method to RESTConnectionHelper
Added function to retrieve users avatar from Mxit.
Added app link functionality to REST Messages.
A temporary fix to address issues with Mxit parsing of messages that have no links attached.
This is necessary once commit 83f08a8 (Add link functionality to REST messages) is added.
(added as a separate commit so that it can easily be rolled back once Mxit fixes their side)
Merge pull request #10 from georgezee/include-message-links

Added app link functionality to REST Messages.
Merge pull request #11 from georgezee/temp-fix-mxit-link-parsing

A temporary fix to address issues with Mxit message parsing
Merge pull request #9 from georgezee/get-user-avatar

Added function to retrieve users avatar from Mxit.
Added a method that allows for persisting rest messages. Still need to make config option to use persistance as optional
[RestConnectionHelper] Used RestMinimalMessageToSend object to be sent, as previous object was causing conflicts with Mxit API service.
[RESTMinimalMessageToSend] Added new object to minimise data sent to Mxit API.