* Add claim page for dmark for more prettiness * Add management command to migrate flows forward * Add flow migration for partially localized single message flows * Recalculate topups more often * Add dmark channel (only can send and receive through courier) * Merge pull request #1522 from nyaruka/headers * Replace TEMBA_HEADERS with http_headers() * Improve mock server used by tests so it can mock specifc url with specific responses * Add method to get active channels of a particular channel type category * Replace remaining occurrences of assertEquals * Fix the way to check USSD support * Dynamic channels: Vumi and Vumi USSD