Simplifying travis file

[BDHernand]

Description

To simplify all .travis.yml file to reduce code duplication

Motivation and Context

We created a script file in the Kitura-Build repo to be called instead of copying the same 4 lines to multiple repo's travis.yml files

How Has This Been Tested?

Ran the code through Travis CI which builds Kitura on linux and mac

Checklist:

• [ ] I have submitted a CLA form
• [ ] If applicable, I have updated the documentation accordingly.
• [ ] If applicable, I have added tests to cover my changes.

[BDHernand]

the last commit "testing travis" was needed to get it to build in travis.

[BDHernand]

@ianpartridge corrected the last commit message and it is running through travis now