Revert "[maven-release-plugin] prepare for next development iteration"

This reverts commit 215ee73395dfb1a1e0958d8e7d8470baf346b18b.
Revert "[maven-release-plugin] prepare release SlipStreamServer-2.0.0"

This reverts commit e6b53454d089bfd4b5f3fd1c199faa6200d10372.