It is a bad practice to put the libraries' path inside them.

This reverts commit 088220ad.

Added more exception catch codes in interpreter. Should now link correctly with boost libraries. Small debug output changes.

    * src/signal/signal-caster.cpp.

     * src/signal/signal-caster.cpp: when type is not registered.

   * include/dynamic-graph/signal-caster.h,
   * include/dynamic-graph/signal.t.cpp.

     * include/dynamic-graph/exception-abstract.h,
     * include/dynamic-graph/exception-factory.h,
     * include/dynamic-graph/exception-signal.h,
     * include/dynamic-graph/exception-traces.h,
     * include/dynamic-graph/signal-caster.h: This enables uses to catch
       a broader class of exceptions with messages using what() method.

    * unitTesting/test_signalcast.cpp.

    * src/signal/signal-caster.cpp.

     * include/dynamic-graph/exception-abstract.h,
     * src/exception/exception-abstract.cpp.

Added an example of caster construction for type vector (dummy cast, similar to the default one, just for the tuto).

Added boost::ublas::vector example to test_signalcast.

    * src/CMakeLists.txt, link to dl,
    * unitTesting/CMakeLists.txt.