add some specs and travis ci integration

Hi,

considering this is a test centric plugin, I figured I´d give it a shot to add some tests around it just for practice. I also added travis integration to demo the specs. See passing build here: https://travis-ci.org/hanneskaeufler/vim-spectacular/builds/44695781

The specs still have their issues, e.g. I cannot make the pass without the `sleep` which seems stupid.

Would you be interested in adding something along those lines?