Update CI tests to check for 0xD in the mustache template files

[wing328]

Description

We need to better way to automatically check for 0xD (^M in vim) in the mustache template files.

Ideally the check should be performed by the CI (travis, shippable or appveyor)

Swagger-codegen version

Latest master

Suggest a Fix

A good starting point is .travis.yml and perform the check using a bash script.

[wing328]

Done via #4526