chore(travis): force the latest version of selenium

This might solve some flakiness on SL. At least Santi said that ;-)
docs: use q-io instead of deprecated q-fs

This recursive process.nextTick error[1] was probably coming from q-fs,
which is not actively maintained. This updates to q-io/fs instead.


[1]: https://travis-ci.org/angular/angular.js/jobs/15391590