add HttpClient, Mailer and Mime components
use range dependencies
raise dependency on symfony/contracts 1.1.3
raise dependency on symfony/polyfill 1.11
raise dependency on doctrine/annotations 1.7
raise dependency on egulias/email-validator 2.1.10
add dependency on masterminds/html5
add dependency on mongodb/mongodb
add dependency on nyholm/psr7
add dependency on psr/http-client

- raise dependency on twig 1.41
- raise dependency on contracts 1.1.1