add CMake to CSXCAD
Merge branch 'CSXCAD-cmake' of git://github.com/guitorri/CSXCAD + some fixes


Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
build: improve cmake handling

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
cmake: use absolute RPATH

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
cmake: include optional local config file

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>