Updating links in Readme.
moved gms- and shp-interface to FileIO-namespace; added a bit of documentation
added GMSH helper-classes to seperate namespace
removed --readNonBlankLineFromInputStream-- since it is not called from anywhere
added legacy interfaces to Legacy namespace
renamed FileIO/MeshIO to FileIO/GmshIO and moved GmshInterface and TetGenInterface on level up
fixed missing namespace changes
Merge pull request #318 from rinkk/FileIOCleanUp

FileIO structure clean up.
Split GMSH and Legacy namespaces.
Remove two unused functions from FileIO.
moved misplaced comment to correct position
Added dedicated file for namespace documentation
fixed doxygen tagging for nested namespaces
Merge pull request #319 from rinkk/NamespaceDocumentation

Namespace documentation
Merge branch 'master' of https://github.com/ufz/ogs into petsc_vector