[#149] Add script that generates python tuples variables from IATI code
lists

Add a script that creates tuples generated from the IATI code lists.
Each tuple is named after the code list but prefixed with IATI_LIST_ and
the words in the code list name are separated by _ and uppercased.

The tuples generated can be used in django model fields for choices
lists. In cases where there are more than two items for each code in the
IATI list additional munging will be needed to create a tuple of
two-tuples that django choices needs.

Add rsr/iati_code_lists.py with a tuple generated from the IATI
Organisation Type code list.
[#149] Add Organisation.new_organisation_type field to use the IATI
Organisation Type code list
Add requests to pip requirements
A little code cleanup
[#121] Extend IATIProjectResource

Add IATIPartnershipResource and IATIBudgetItemResource

Use the above classes in IATIProjectResource

Some code cleanup
[#121] Additions and changes to the XSLT

Change the description tag to use akvo:type selector

Add templates for budget and participating-org

Change how activity-date is handled
[#121] Add importing script for Cordaid XML

Add api/cordaid_importer.py. It is not fully functional at this point.