Add international_development_fund schema

This format will be published by DFID editors via Specialist Publisher.
Merge pull request #274 from alphagov/add-international-development-fund-schema

Add international_development_fund schema
Specify encoding as UTF-8 when reading JSON

This isn't necessary in dev, or when running from the command line on a
preview box, but in the live preview environment, some pound signs in a
schema file were causing a:

    Encoding::InvalidByteSequenceError: "\xC2" on US-ASCII

error when loading the schema json (in schema_config.rb, "load_json")

We're not sure why there's a difference; current theories are that it's
due to something missing in locale data.  Rather than investigate right
now, we're just going to specify that the file should be read as UTF-8.
Merge pull request #275 from alphagov/read-json-as-utf8

Specify encoding as UTF-8 when reading JSON
Rename idf_sector to development_sector

We don't want to expose the term idf_sector anywhere, so it needs to be
changed to development_sector.
Merge pull request #276 from alphagov/rename-idf-sector

Rename idf_sector to development_sector
Add extra AAIB fields

Adding extra fields for aircraft_type, registration and location to the
AAIB reports.
Merge pull request #277 from alphagov/add-extra-aaib-fields

Add extra AAIB fields
Update the README about popularity information
Merge pull request #278 from alphagov/popularity-readme

Update the README about popularity information
Stemming override for 'nationality'
Stemming override for 'complaint'
Remove 'complaint' from synonyms
Merge pull request #279 from alphagov/stemming-20140729

Stemming override for 'nationality' and 'complaint'