misc minor fixes & rubocop style

Hi @effkay,

* rubocop -a again (it gets stuck in the page model?)
* gem dependency fix
* regenerated spec_helper and added kuhsaft-specifics
* add a few translations
* available_locales will be reset before each spec
* should fix #195 

~~what is still existent: "kuhsaft_development already exists"~~


Thank you very much,
Alex