Released sweble-engine-2.0.0

* sweble-engine b728fb2...98e894d (1):

    commit 98e894d2cd70c8c58a7800992b3fea58db50a8be

        [maven-release-plugin] prepare release sweble-engine-2.0.0
Made path to sweble-engine relative in .gitmodules
Added hddiff-project as submodule