Set default values for the arguments of create_project
Adjust error message to reflect the actual problem more appropriately
Add an old_distro_name argument to the map_project method

This allows to update both package name and distribution at the same time
Add support for the old_distro_name argument when editing a mapping
Port create_project in the unit-tests to use anitya.lib.create_project
Add unit-tests for anitya.lib
Fix the Log.search so that the from_date is the date from which the logs are returned
Expand the unit-tests for anitya.lib.model
Ignore SQLAlchemyError that we cannot reproduce in our tests
Add unit-tests for anitya.lib.plugins