[NEW] Componentwise and normwise relative backward errors may be used as stopping criteria for linear solvers (except for BiCGStab(L)

git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6875 04224531-1f84-46d8-96ce-875b9e37dce3
[NEW] Major revision in ElmerGrid for parallel operation: Memory savings implemented by directly constructing sparse matrices (for Metis). Implemented new hierarchical partitioning routine that can be used to first partition boundary elements with Metis, and thereafter the remaining bulk elements. The user may also extend the partitioned boundary with additional element layers to the bulk elements (default is one). 


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6876 04224531-1f84-46d8-96ce-875b9e37dce3