Reorganized to support debian packages

1. Reorganized include files so they are included as <ert/lib/file.h>
2. Renamed libraries:
    - libgeometry -> libert_geometry
    - libwell -> libecl_well
3. Added SOVERSION (1.0) to all libraries.
4. Added build switches to build tests and applications.
5. Small build changes to simplify Resinsight build.