Update 2-create_your_device_and_message_classes.md

wrong link to "Step 3" corrected
Update 3-importing_dabpushnotificationsbundle_routing.md

unclosed yaml block closed
Update 4-integrating_with_FOSUserBundle.md

wrong link to "Step 5" corrected
Update 6-integration_with_safari.md

corrected header step number (5 -> 6)
Merge pull request #1 from incrediblecube/patch-1

Update 2-create_your_device_and_message_classes.md