This reverts commit 8fca0b1a.
       Move python interpreter in dynamic-graph-python.

       This reverts commit 0b9f9528.
       Move python interpreter in dynamic-graph-python.

     * src/CMakeLists.txt,
     * tools/CMakeLists.txt.

    * include/dynamic-graph/interpreter.h,
    * src/CMakeLists.txt,
    * src/dgraph/interpreter.cpp,
    * tests/CMakeLists.txt,
    * tools/dg-python.cpp: new,
    * tools/CMakeLists.txt: this adds a dependency to  python in dynamic-graph.

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

	 * src/signal/signal-caster.cpp: cut long lines for function
	   SignalCaster::registerCast.

     * src/signal/signal-caster.cpp.

     * include/dynamic-graph/signal-caster.h,
     * src/signal/signal-caster.cpp: if a typename is registered several times,
     throw only if pointers to type_info differ. When loading python modules,
     for some reason, global variables are constructed several times.

    * src/signal/signal-caster.cpp.

     * src/signal/signal-caster.cpp.

    * src/command/value.cpp: operator= should assign this.

    * CMakeLists.txt,
    * include/dynamic-graph/linear-algebra.h,
    * src/CMakeLists.txt.

    For homogeneity, we use jrl-mal for matrices and vectors.

	* include/dynamic-graph/command-getter.h,
	* include/dynamic-graph/command-getter.t.cpp,
	* include/dynamic-graph/command-setter.h,
	* include/dynamic-graph/command-setter.t.cpp,
	* include/dynamic-graph/command.h,
	* src/command/command.cpp.

       * src/command/value.cpp.

    * include/dynamic-graph/value.h,
    * src/command/value.cpp.

       * src/command/command.cpp.

    * include/CMakeLists.txt,
    * include/dynamic-graph/command-setter.t.cpp,
    * include/dynamic-graph/value.h,
    * src/command/value.cpp.

    Types for vector and matrix are boost::numeric::ublas::vector<double>
    and boost::numeric::ublas::matrix<double>.

       * include/dynamic-graph/command-getter.h,
       * include/dynamic-graph/command-setter.h,
       * include/dynamic-graph/command.h,
       * include/dynamic-graph/entity.h,
       * include/dynamic-graph/value.h,
       * src/command/command.cpp,
       * src/command/value.cpp.

	     * src/CMakeLists.txt.

    * src/command/value.cpp.