CRM-2475 Dedupe: upgrade to use API 2

Fixed in a series of commits. Note: API 2 doesn't currently handle all of the fields handled by API 1 (see the comments at CRM_Dedupe_Merger::$validFields), so there are some regressions at the moment, but this is more of an API 2 issue.

The code has been simplified, but needs CRM-2542 resolution to fully work again. Reopening 'till CRM-2542 is resolved.

Resolved in r12852.

verify for 2.0

Please follow below steps:

1. Create two contact with same first name. but last name and email Ids should be different.

2. Update the dedupe rule.
make weight for first name =10
threshold = 5

3. Click on find duplicate contact

4. Then you will get the list of both contacts.

5. Click on second name .

6. Click on merge.

7. Check all check boxes for merge (check the check box present in label which select all check boxes for merging records ).

8. When u hit the Save you will get error.

What Kiran found out is basically an issue when we try merging a contact that represents the currently logged-in user. When we delete that user after merge, this happens; we shouldn't allow merging of that contact (only with that contact).

Fixed in r12961.