patch: add accessor methods to properties

[John W. Eaton]

On 15-Jun-2007, Shai Ayal wrote:

| As one more step towards a c++ interface to object graphics I attach
| a patch which adds a get_XXX accesor methos to each property XXX.
| This is done using a macro ADD_PROPERTY for all properties except
| for 4 axes_properties which are a special case since they need to be
| mutable. If more properties like these pop up, we could add a
| special ADD_MUTABLE_PROPERTY macro

OK, I applied this patch and went ahead with the mutable macro.  I did
it like this:

  #define OCTAVE_GRAPHICS_PROPERTY_INTERNAL(TAG, TYPE, NAME) \
    private: TAG TYPE NAME; \
    public: const TYPE& get_ ## NAME () const { return NAME; } \
    private:

  #define OCTAVE_GRAPHICS_PROPERTY(TYPE, NAME) \
    OCTAVE_GRAPHICS_PROPERTY_INTERNAL ( , TYPE, NAME)

  #define OCTAVE_GRAPHICS_MUTABLE_PROPERTY(TYPE, NAME) \
    OCTAVE_GRAPHICS_PROPERTY_INTERNAL (mutable, TYPE, NAME)

and also added #undefs for these at the end of graphics.h.

Thanks,

jwe