Try /media/download if /media/thumbnail returns 404

Makefile

include/mtxclient/http/client.hpp

lib/http/client.cpp

lib/structs/events/tag.cpp

lib/structs/responses/common.cpp

lib/structs/responses/empty.cpp

lib/structs/responses/messages.cpp

lib/structs/responses/notifications.cpp

lib/structs/responses/sync.cpp

tests/fixtures/kiwi.svg

tests/media_api.cpp