Fix travis badge reference
Fix travis badge reference

It should be referring to 'master' and not the 'travis' branch. Oops.

kirbyfan64/breathe,AnthonyTruchet/breathe,kirbyfan64/breathe,RR2DO2/breathe,AnthonyTruchet/breathe,kirbyfan64/breathe,kirbyfan64/breathe,AnthonyTruchet/breathe,AnthonyTruchet/breathe,RR2DO2/breathe