[MeshLib] Element: Removed unused lines.
[MeshLib] Testing traits as template in TemplateLine impl.
[MeshLib] TemplateTri: Traits as template.
Forward additional information for local assembly.
Fixed merge mistakes.
[AssemblerLib] Overloaded SerialExecutor::execute().

The overloaded version takes a third argument. This argument is used
needed properties in the local assembler.
[AssemblerLib] Overloaded VectorMatrixAssembler::operator().

The overloaded version has a parameter for data needed by the local assembly process.