fixes and refactoring for contests aliases
changed node version in dependencies
changed node version in travis.yml
set node version in travis.yml
added redirection to referrer after login
contest.firstImage don't work
fixed getByContest function
fixed tests
changed way to auth and some localized
bug with photos in the slider on the homepage and sign-out
private contests don't shown on the homepage
some improvements for mobile layout
merge slider-for-homepage