Fix loss of solutions in multiSPDE


git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1798 b0c55286-4f34-0410-a049-a1e7e93b0762
Move 'decompose' to separate package


git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1799 b0c55286-4f34-0410-a049-a1e7e93b0762