Added CMake option OGS_CPU_ARCHITECTURE which defaults to native

See
http://docs.opengeosys.org/docs/devguide/advanced/configuration-options

Linear solver library setup

Petsc, lis, and a default implementations are provided.

Was because of an outdated FindGit-module in ThirdParty/cmake-modules.

[AL] Rename getGlobalIndices<ORDER>() functions.

Remove template specialization and name the functions
correspondingly.
Improve documentation.

[BL] Quicksort: Fix miscalculated second limit.

Easier git finding

Global index type

The preprocessor scheme follows the NumericsConfig scheme.

Check for equality of the types

This also breaks possible circular includes.

Renamed AssemblerLib::SerialVectorMatrixBuilder.

Update petsc cmake scripts

Make solver interface unique