------------------------------------------------------------------------
From version 2.0.5 to version 2.0.6 [18 Jan 2002]
* Fixed the header files vf_state.h and vf_sub_state.h.
    The problem was that both these headers defined the same
    constants used to encode the node flags. This prevented including
    both the headers in the same source file. The problem was
    pointed out by Keishi Sadanami.
    Now the mentioned constants have been moved to inside the
    private part of the corresponding classes (VFState and VFSubState),
    where they logically belong.

------------------------------------------------------------------------
From version 2.0.4 to version 2.0.5 [17 Dec 2001]
* Changed the way attributes are destroyed or compared in ARGraph_impl.
    Instead of functions, now there are instances of abstract classes
    AttrDestroyer and AttrComparator which are responsible for 
    deallocating or comparing node/edge attributes. The methods
    SetNodeDestroy/SetEdgeDestroy and SetNodeCompat/SetEdgeCompat
    have been superseded by the new SetNodeDestroyer/SetEdgeDestroyer
    and SetNodeComparator/SetEdgeComparator (although the former
    are retained for compatibility with previous versions).
      The advantage in the new scheme is that the objects may
    store some context information without the need to resort to
    global variables. For example, an AttrDestroyer may hold a 
    reference to a memory pool to which  the destroyed attribute
    has to be given back in order for it to be recycled.
    The documentation has been changed accordingly.

------------------------------------------------------------------------
From version 2.0.3 to version 2.0.4 [7 Nov 2001]
* Fixed a bug in argraph.cc, for class ARGraph_impl
    The bug was in the implementation of method SetEdgeAttr,
        causing it to enter a non-terminating loop; also, this
	method was lacking the code to update the in_attr field,
	thus leaving the graph in an inconsistent state.

* Changed reading methods used in argraph.cc, for class BinaryGraphLoader
    The BinaryGraphLoader class used the istream::get(char &) method
        for reading a byte. Now this method is deprecated, and
	recent compilers (e.g. VC++6.0) do not recognize it. 
	Thus, now the int istream::get() method is used instead.

* Added a missing define in xsubgraph.h
    The xsubgraph.h header file contains an #ifndef to prevent multiple
        inclusions; however, the corresponding #define was missing, 
	making it possible to have multiple inclusions of the file.
	Anyway, this was more an inconsistency than an error, since
	the header file only contains a function prototype, and
	multiple inclusions cannot cause any harm.

------------------------------------------------------------------------
From version 2.0.2 to version 2.0.3 [16 Oct 2001]
* Fixed a bug in argraph.cc, for class ARGraph_impl
    The bug, reported by Brian Kelley and L. Shyamal, was in the
        destructor, and caused a memory leak when a graph
        was deallocated.

* Changed headers used for C++ iostream library
    All the references to <iostream.h> and <strstream.h> have
        been replaced by <iostream> and <strstream>, conforming to
	the C++ standard. This could break things on older
	compilers, but can make newer ones happier (especially 
	Visual C++).

* Fixed non-standard use of new
    As reported by Brian Kelley, VisualC++ does not like
        the parentheses in constructs like:
	    new (byte*)[n]
        Those parentheses have been removed wherever they
	occurred in the library code.

------------------------------------------------------------------------
From version 2.0.1 to version 2.0.2 [3 Sep 2001]
* Fixed a bug in argraph.cc, for class argraph_impl
    The bug, reported by Thomas Mailund, was in the destructor,
	which called the edge-attribute destroy function instead of the
	node-attribute one.

* Fixed an error in the documentation
    Examples in the quick tour (sec. 3.1 and 3.2) used the costructor of 
	class Graph passing an ARGLoader object, instead of a pointer to an 
	ARGLoader as required by the constructor. This error was reported 
	by Torsten Schindler.

* Removed the file xistrstream.h and the xistrstream class
    This class was introduced to fix a bug in gcc2.7.2; however it 
	introduced a dependency from the iostream library
	implementation that prevented compilation on non-GCC compilers.

* Added the VF2MonoState class
    This class, which was cited in the documentation but not
    included in the library, performs monomorphism matching using
	the VF2 algorithm. The corresponding files are vf2_mono_state.h and
	vf2_mono_state.cc.

------------------------------------------------------------------------
From version 2.0 to version 2.0.1 [5 Jun 2001]
* Fixed a bug in argloader.cc, for class BinaryGraphLoader


