Minor update of OpenModelicaUsersGuide - authors list

OpenMOdelicaSystem - added test case building chapter and
updated authors list
ModelicaMetaProgramming - added introduction about
modeling too extensibility and a chapter (unfinished)
at the end about metaprogramming and code quoting.

git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk/doc@2685 f25d12d1-65f4-0310-ae8a-bbce733d8d8e