fix(*): add dummy email settings for running tests
feat(accounts): add header links for logged-in user
feat(common): add new style for buttons: "hollow"

The "hollow" style uses a dark grey font and transparent background color.
fix(common): apply the hollow button style to header links
Merge pull request #47 from brasilcomvc/feat/auth-header-actions

Guest and logged user header links
feat(common): create a button style for Facebook
Merge remote-tracking branch 'github/feat/facebook-button'

Conflicts:
	brasilcomvc/common/static/styl/defs/mixins.styl
	brasilcomvc/guideline/templates/guideline/ui.html
requirements: put back upstream django-pipeline
feat(heroku): adjustments for Heroku deployment
fix(travis): remove nodeenv
feat(staticfiles): add S3 support
feat(runtime): Change runtime to 2.7.8

django-storages do not support Python 3, as we're dependent on it
the current Heroku runtime is downgraded to Python 2.7.8

Issue: http://code.larlet.fr/django-storages/issue/155/python-3-support
fix(readme): add warning regarding S3 support and Python 3