outbound: fixed duplicate traits; added fixtures

modified mapper to delete duplicate traits, solving issue #16609 in zendesk
rewrote tests to use fixtures, added tests for ios/android tokens
Merge branch 'master' of ssh://github.com/segmentio/integrations into fix-outbound-duplicate-traits
Style fixes
Merge pull request #207 from segmentio/fix-outbound-duplicate-traits

Fix outbound duplicate traits