GNUnet 0.6.4a released

This release fixes a few minor bugs, including some cleanup of the semantics 
of gnunet-insert (with respect to directories and namespaces when passing 
multiple arguments), various bugfixes for rare error conditions (for example 
an unclean shutdown if binding to TCP port failed) and some improvements to 
the build process (giving the user earlier and better feedback if 
dependencies are not satisfied).

As usual, GNUnet 0.6.4a is available at http://ovmj.org/GNUnet/ and 
(eventually) will be distributed to all GNU mirrors.  

Christian