Proposed change for Travis CI (#31)
Proposed change for Travis CI (#31)

* Proposed change for Travis CI 

The following updates have been done to improve readability and convenience of CI builds Travis CI:
- Use `jobs` instead of `matrix`
- Use `stages`
- Give proper names to each job, instead of relying on environment variables
- Ensure release deploys are only run on `master` branch

* Set SWIFT_VERSION environment variable on Linux

scottrhoyt/SwiftyTextTable,scottrhoyt/SwiftyTextTable,scottrhoyt/SwiftyTextTable