Remove sources, functions are no longer used.
Updated changelog and reorganized the most significant changes are first.
Migrations now work with any set of languages.

Previously the migrations were hard-coded to work with databases where
the LANGUAGES setting contained at least English (en). This meant that
new databases that did not use English could not use the migrations,
though they could still force a syndb to create the database.

The migrations were updated to replace names such as 'name_en' or
'description_en' that were defined through the migrations to use
the set of internationalized names, 'name_pt_pt', 'name_pt_br' that
were generated from the LANGUAGES setting.