Send optional AFP messages for vetoed files

New option "veto messages" can be used to enable sending messages.
Then whenever a client tries to access any file or directory
with a vetoed name, it will be sent an AFP message indicating
the name and the directory.

Feature request #81.
New boolean volume option "delete veto files"

If this option is set to yes, then Netatalk will attempt to
recursively delete any vetoed files and directories.

Remove obselete code that tries to delete dangling symlinks, this
is not necessary anymore since Netatalk support UNIX symlinks.

Modify behaviour of the VFS function deletecurdir of the "ea" VFS
module so it deletes all files beginning with "._".

From feature request #82.
systemd unit dir is /usr/lib/systemd/system now
FPExchangeFiles must only switch data file, not metadata

In Netatalk 3, afp_exchangefiles() moves the metadata EAs togehter with
the files, so we must copy the metadata EAs back at then end.

Fixes bug #521.
Remove obsolete variable
Prepare 3.0.5 release
Bump version
twisted u_name and m_name

Fix Bug#523.

Additional Info:
The following line in ofork.c may also be wrong.

    /* Somone has used write_fork, we assume file was changed, register it to file change event api */
    if (ofork->of_flags & AFPFORK_MODIFIED) {
        struct dir *dir =  dirlookup(ofork->of_vol, ofork->of_did);
        bstring forkpath = bformat("%s/%s", bdata(dir->d_fullpath), of_name(ofork));
        fce_register(FCE_FILE_MODIFY, bdata(forkpath), NULL, fce_file);
        bdestroy(forkpath);
    }
Add indication to help string that --with-ldap takes an optional path
DSI_SERVQUANT_DEF is 1048576 now
Don't force S_ISGID for directories on FreeBSD, bug #525
Fix error handling when trying to set ACL on not existing rfork
Add support for ZFS ACLs on FreeBSD with libsunacl

From FR#83.
Active Directory LDAP queries for ACL support

AD stores users and groups under the same subtree which broke our naive
search strategy. Add LDAP options "ldap user filter" and "ldap group filter".

Fixes Bug #526.
Explanation of "veto message" is wrong.

and some fixes.
Move Spotlight UNIX domain socket to /netatalk/
Fix dalloc_value_for_key usage
Merge remote-tracking branch 'origin/branch-netatalk-3-0' into develop

Conflicts:
	NEWS
	VERSION
	doc/manpages/man5/afp.conf.5.xml
	doc/www/ReleaseNotes
	libatalk/util/netatalk_conf.c
	macros/summary.m4
	man/man5/afp.conf.5.in