Add support for Travis CI

This adds support for buildin sqerl on Travis CI, key notes:

* Currently, we only support > R16B01 (R16 fails to build due to
  timeout). We have another PR out for R17/17.0 support
* We needed to add a dialyzer.ignore file (and hook it up in
  concrete) in order to avoid breaking on a eunit dialyzer warning
  that is inconsequential.