Message center big update

- Add a mapping for transmitting gifts to GMC
- Bug fixed for depart action
- Prepare depart method
- New child state : deallocated, for deallocation of children
- New message states : new, pending, success, fail
- We can now receive message acknowledgements
- Incoming actions adapted but not yet ready
- Code refactoring
- UPSERT constituent when sponsor name changed
- ...
New tests for GMC Messages.

- Various bug fixes
- Tests are not working yet
- New method for middleware fetching gift information easily
child_translated_values_view created
Add functionalities to get Infos button
fix project_compassion_views and create country_compassion_view
create english child description
fix repetitions in child_description_en.py and PEP8
fix country name in view, create child_description_it.py and PEP8

- child_description_de|en|it.py refactored + PEP8

- Resolve conflicts

reviewed code corrected

- reviewed code corrected + PEP8
Add unique_id field in case study

- Modified request_id to string field

- Use working child codes in tests.

- include child unique id in case study retrieval
Message Center bug fixes + PEP8

... Tests are now OK !
add request_id field. Bug fixes.

- Fixed write child code bug

- Don't raise error if none image is found for child
Incoming messages events and child pictures object.

- Incoming messages can have different events.
  Update method on Children handle the events differently
  (casestudy, picture, transfer)
- New object for storing children pictures (TODO)
Moved child pictures in a separate object

- Child pictures are attached to a new object
- UpdateChild message will now get only the pictures for event
  NewPictures.
- Write_date accessible to middleware from object res_partner
Retrieve suspension information, reset failed messages.
Need key is now a functional field
Set object_id on messages after allocation
Create get_exit_details method
rebase + bugs fixed