Adding cli testing and Travis CI config.

Dave,

Here's the pull request.  

The cli testing does not install parcelify globally, which works in my environment after locally installing the rather large list of dependencies.  You may want to do things differently and I understand if so.  The win in my opinion is using the version of parcelify that is being tested by Travis CI and not whatever version is in npm.

Some of the clunky parts of the cli testing are the sleep statements in watch mode testing.  I feel like either we use a polling method for a set duration of time or just crank up the sleep, since I foresee an occasional false error due to slow IO and the current 3 second wait.  Also the transforms cli options have yet to be added to the test suite, so that is a short TODO.

All in all without testing I feel pretty good about this Pull Request.  Hope you do to.

Elliott