STLplus C++ library collection SVN stlplus3

Summary: Bug fix for Linux - cannot reuse va_list parameter

rework vdprintf in a more standard way

update version number for next release

This commit was manufactured by cvs2svn to create tag 'stlplus3-03-13'.

Reworked the path_exists algorithm. The algorithm was giving up the
search too soon in the case when one arc went to a visited node,
sibling arcs didn't get visited. I have rewritten the algorithm
completely using a simpler method. Also changed the test pack to
compare the output of the path_exists algorithm with the all_paths algorithm.

Reworked the path_exists algorithm. The algorithm was giving up the
search too soon in the case when one arc went to a visited node,
sibling arcs didn't get visited. I have rewritten the algorithm
completely using a simpler method. Also changed the test pack to
compare the output of the path_exists algorithm with the all_paths algorithm.

replaced digraph::clear with a more efficient implementation - this is called from many places including the destructor

minor edit incorrect message, added extra progress check

Synchronised with source code

Replaced the simple_ptr with DJDM's latest update with deferred
allocation of the alias count - now working in Visual Studio. Also
slight mod to test to avoid trying to pass a temporary by reference.