Refactor #get_institution_name

Hi Lee,

This Pull Request suggests a few refactors to DRY the codebase. Basically, `#get_institution_name` now uses `#get_domain`.  

I hope you like it, and thanks for swot!
Simeon

* Refactor `#get_institution_name` to use `#get_domain`
* Define `#get_path` to get file path from domain
  * `#match_academic_domain?` and `#name_from_academic_domain` use `#get_path`
* Strip input `text` within `#get_domain`
* Replace `File.open` with `File.read` in `#name_from_academic_domain`
  * Be more concise
  * Ensure file is closed
* Add Travis CI
  * Requires [activating a service hook](http://about.travis-ci.org/docs/user/getting-started/#Step-two%3A-Activate-GitHub-Service-Hook)