Temporary branch for making the cdo tests from the directory "test" running with "make check" and "make distcheck"

This should be possible to run from VPATH build, too

Instead, CDI functionality can be build into CDI
* by build, link + install a shared CDI library
* by linking to CDI object files directly
Both is done from the libcdi subproject directory (refs #492)

Add libtool support for linking cdo (refs #82)
Make use of CDI's m4 library for configure options
Use Json file for saving/representing configuration status (refs #371)

closes #228