libssh2 1.2.8

This release includes the following changes:

 o added libssh2_free, libssh2_channel_get_exit_signal and
   libssh2_session_handshake
 o SFTP read/write remade and now MUCH faster, especially on high latency
   connections
 o added new examples: ssh2_echo.c, sftp_append.c and sftp_write_sliding.c
 o userauth: derive publickey from private
 o NEWS: now generated from git

This release includes the following bugfixes:

 o Support unlimited number of host names in a single line of the
   known_hosts file.
 o fix memory leak in userauth_keyboard_interactive()
 o fix memory leaks (two times cipher_data) for each sftp session
 o session_startup: manage server data before server identification
 o SCP: allow file names with bytes > 126
 o scp_recv: improved treatment of channel_read() returning zero
 o libssh2_userauth_authenticated: make it work as documented
 o variable size cleanup: match internal variable sizes better with the sizes
   of the fields used on the wire
 o channel_request_pty_size: fix reqPTY_state
 o sftp_symlink: return error if receive buffer too small
 o sftp_readdir: return error if buffer is too small
 o libssh2_knownhost_readfile.3: clarify return value
 o configure: stop using the deprecated AM_INIT_AUTOMAKE syntax
 o Fixed Win32 makefile which was now broken at resource build
 o kex_agree_hostkey: fix NULL pointer derefence
 o _libssh2_ntohu64: fix conversion from network bytes to uint64
 o ssize_t: proper typedef with MSVC compilers
 o zlib: Add debug tracing of zlib errors
 o decomp: increase decompression buffer sizes

This release would not have looked like this without help, code, reports and
advice from friends like these:

 Alexander Lamaison, Alfred Gebert, Guenter Knauf, Dan Fandrich,
 Daniel Stenberg, Jasmeet Bagga, Joey Degges, Mark Smith, Peter Stuge,
 Pierre Joye, Simon Josefsson, TJ Saunders, Tommy Lindgren
 
        Thanks! (and sorry if I forgot to mention someone)