Initial release

[iliapolo]

Implement the initial release, should include:

• Automatic Github release (no assets)
  When code is pushed into the release branch, the releaser should create a Github release that:

  1. Version is derived from the issue associated with that commit.
  2. Changelog is derived from all non released, issue related, commits pre-dating this commit.
  3. The corresponding branch (from the PR) is deleted.
  4. Master branch is updated to be the tip of the release branch.

  When should we not release:

  1. The commit does not relate to a Pull request (should be discouraged)
  2. The pull request does not relate to an issue (should be discouraged)
  3. The issue is not marked with one of the release labels

• Ci Detection (Only travis for now)
  When running in a CI, the releaser should look at the appropriate env variables to determine if the current build should be released. This is to prevent releasing branches and builds other than the release branch.
  If no CI system is detected, we should only release if explicitly specified, this is for allowing users to release from any environment.

[iliapolo]

This issue is part of release 0.4.0