Secret URL registration. Closes #1507

client/routes/router.coffee

i18n/en.i18n.json

packages/rocketchat-lib/package.js

...chat-lib/server/methods/checkRegistrationSecretURL.coffee

packages/rocketchat-theme/assets/stylesheets/base.less

packages/rocketchat-ui-login/login/form.coffee

packages/rocketchat-ui-master/master/blankLayout.html

packages/rocketchat-ui-master/package.js

packages/rocketchat-ui/package.js

packages/rocketchat-ui/views/404/invalidSecretURL.html

server/methods/registerUser.coffee