CRM-10397 Pay Later Improvements

Update title and description of Contributions by Organization

CRM-12613 - Forward port REST.php

This file had been held back from normal merge-forward due to
merge-conflicts.  Investigating upstream/master, it seems that there were
two changes that may have been source of conflict:

 * 2ede60ec - This is formatting change and a bad-commit of a debug code
 * c5f77b41 - This is a real functional change but was backported (and
   further fixed) in 4.3, so 4.3's version is better.

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* CRM-12613: Resolve merge of REST.php (4.3=>master)
  http://issues.civicrm.org/jira/browse/CRM-12613

CRM-12628 rename non-standard MailingGroup DAO instead of hack. Also add...

Test fixes (contribution soft credit, tweaks on previous fixes)

Register and use the autoloader during API calls

Test fixes including activity contact api, mailing contact api, soft contribution api

fix includes -
- using spec function to provide documentation, enforce required fields, provide default, enforce options
- using standard api function to process 'limit', 'sort' etc
- skipping checks for getByID because in this area the api cannot be made standard
NOTE that the default limit has been set to the api default (25). Making
this non standard for a particular use-case doesn't make sense.

Preferred calling method is
$params['options' => array('sort' => 'contact_id DESC', 'limit' => 50,
'offset' => 200)

re-fix mailing contact api

CRM-12626 Fix test by no validating arrays passed into string fields

Fix an error in 4d1d7aca - get short name from classname