SGF-283 - Polish changelog structure.

Moved = line below the additional remarks to make sure we can detect the place where to add new changelog entries when automating releases.
SGF-283 - Removed obsolete repository declarations.

To make sure the release automation has a single repository declaration to work with I removed the obsolete release and milestone repository declarations. The snapshots contains the milestone repo, which in turn contains the release one, so that only one of them has to be declared depending on which artifacts you want to see.
SGF-283 - Updated changelog.
SGF-283 - Prepare 1.4.0.RC1.

Upgraded to Spring Data Commons 1.8.0.RC. Switched to milestone repository.
SGF-283 - Release version 1.4.0.RC1.
SGF-283 - Prepare next development iteration.
SGF-283 - After release cleanups.