GCR iteration: Recompute the true residual when restarting and check the accuracy of the iterated residual norm when the convergence criterion is met

git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6893 04224531-1f84-46d8-96ce-875b9e37dce3
Some additional keywords to projector stuff. Also enabled saving of projectors to file in parallel case.

git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6894 04224531-1f84-46d8-96ce-875b9e37dce3