fix(travis): add missing config

This fixes travis complaining about not able to find the less module:
https://travis-ci.org/dothiv/dothiv/builds/22109899
fix(travis): use locally installed karma bin
fix(travis): update e2e test config
fix(travis): add firefox launcher
fix(package.json): karma 2 requires changes for the tests
fix(travis): disable e2e tests
fix(dhTeaser): better detection of extra element
chore(travis): added log output only listing CRITICAL errors
Merge branch 'coderbyheart-fix-dhTeaser-tests' into fix-travis
fix(travis): use mysql db
Merge pull request #23 from dothiv/fix-travis

Fix broken tests on travis-ci.org