OSX Travis build backlog borderline unusable

[guruvan]

Travis is taking 15-60minutes typically to start builds for OSX (and Xenial builds too)

This prevents rapid iteration of the build system, and will affect downstream builders using the project.

Future releases will have to provide ability for local OSX VM builds.

See travis-ci/travis-ci#7304 for more info on the state of Mac Infrastructure at Travis

( much of the fault lies in Apple - the combination of their licensing and their lack of enterprise class server hardware makes it highly difficult to provide a CI environment for OSX apps that is both public and fast)