[#710] Fix ProjectResource.get_object_list()

ProjectResource.get_object_list() does not return unpublished projects
when the API is queried by an authenticated user.

Fix by calling ApiKeyAuthentication.is_authenticated() to check if the
user is authorized to view unpublished projects.
[#710] Fix RainActivity.rsr_id() and RainActivity.internal_id()

The xpath for those two methods is searching from the root (xpath search
string starts with "//") in the belief that the tree only encompassed
one activity. But this seems not to be the case resulting in _all_
activities being searched.

Fix by removing the "//".
[#710] Add more settings

Add settings for the URLs to use when fetching the RAIN organisations
and activities XML.

Add settings for a pair of log labels.
[#710] Add functions for importing XML from file system or internet.

Add load_xml(). This function is moved from rain_project_upload.py

Also add save_xml() to allow saving of the fetched XML for logging
purposes.
[#710] Better logging for organisation_upload.py
[#710] Import organisation XML from URL

Fetch organisation XML from the RAIN website.

The XML fetched is saved for logging/debugging in the same folder as the
import logfiles.
[#710] Import activities XML from URL

Fetch activities XML from the RAIN website.

The XML fetched is saved for logging/debugging in the same folder as the
import logfiles.
[#710] Better logging for post_import.py
[#710] Add category, sync_owner and publishing

Add methods for setting the category, sync_owner and publishing status
of all imported RAIN projects.
[#710] Import activities XML from URL

Fetch activities XML from the RAIN website.
Merge pull request #755 from akvo/hotfix/710_rain_iati_import

[#710] rain iati import