Bump version to 0.4rc1
Update Changelog

Update Changelog and change it's format to be in line with the one from
the Synnefo project.
Prepare for release 0.4

Remove RC versions from Changelog and add release date for
version 0.4.
Merge branch 'release-0.4'
Bump version to 0.4
Merge branch 'master' into develop

Conflicts:
	version