made xfrout use the dns python wrappers instead of the boost.python one
(still needs boost.python for the wrappers for sending sockets around)

also fixed a few other problems in xfrout;
- UNIX_SOCKET_FILE (the socket that is used to send other socket descriptors over) only worked if installed, updated to use @abs_top_srcdir@/auth_sock_conn for the domain socket file (for now, where should we really put this?) Also updated bin/auth/main.cc to use this one if run from source tree
- That file descriptor that is passed wasn't closed, so after a while the system would run out of file descriptors. Added os.close(fd) for that to xfrout. We might want to think about adding this to our send_fd/recv_fd lib
- Other (temporary) workaround; When the AXFR response is rendered, it triggers truncation. So for now I used renderer.setLengthLimit(65535). But we might want to simply make multiple message packets within the stream.

(all three of these problems also occur in trunk/ btw, but since all of them might be temporary and i'm focusing on the main wrappers here, i committed them here for now)


git-svn-id: svn://bind10.isc.org/svn/bind10/experiments/python-binding@1828 e5f2f494-b856-4b98-b285-d166d9295462