Add leading 0 for the month

This makes the tests fail on my system, for some reason.
Setup development environment with Composer

I had to add a dev-dependency on doctrine/orm 2.3.4, because it wouldn't
work with 2.4 . I chose 2.3.4 because it is what appears in the
.travis.yml . I removed this requirement from .travis.yml since it is
handled with Composer now.
Merge pull request #90 from greg0ire/ease_contributions

Ease contributions