[la.solver.istl]
* fix header guard
* encapsulate everything istl in a try/catch block
[la.container.interfaces] updated operator<<
* vectors are now one value per line
* matrices use ' ' and ',' instead of ',' and ';'
[la.container.istl] added custom operator<<
* makes use of the sparsity pattern to avoid access exceptions
[grid.provider.cube] refine initial grid in case of aligrid conform