BugFixes please merge to release.

Distribute matrixmarket.hh
AMG: make x consistent even if there is only one level
galerkin.hh: Initialize Matrixblock correctly
splvers.hh: Always call pre mthod of the preconditioner _before_ using
the operator. Thus x is consistent and the computed defect will be,
too.
matrixmarket.hh: use int instead of size_t as template parameter as
this is the case for the FieldMatrix, too.

[[Imported from SVN: r1179]]