User homes directory names

Fix an issue with user homes when user home directory has not the
same name as the username.

Fixes bug #497.
Add checks for required packages
typo in netatalk.c
Several fixes in ad_conv_dehex()

Testing whether we need to perform dehexing was done by a simple
strchr(':'), thus names only containing a single ':' would trigger
dehexing even though they might not contain the relevant strings
":2e" or :2f".

Also fix a ressource leak in bfindreplace() and simplify the
check whether a rename took place in enumerate.c.
AFP statistics via dbus IPC

Fix PAM config installation. make distcheck was failing on Solaris
in uninstall, because the uninstall target ran some `rm -f PAMFILE`
where PAMFILE is hardcoded to /etc/pam.d. The resulting EPERM
causes the make target to fail.
Add dtrace provider 'afp' and dtrace probes

There are three dtrace probes:
- all AFP functions, passing the function name as argument
- AFP read and write, passing the IO size as argument
- all CNID functions

In order to be able to simply differintiate between disk IO and
network IO, replace all occurences of read and write on sockets
with send/recv, and replace the use of writev in the logging code
with two calls to write.
As a result, using dtrace probes for read() and write() syscalls
can be used to gather metrics for disk IO, while probing send(),
recv() and writev() probe network IO.
Fixes
Add checking for and linking with libgthread
Reload groups when reloading volumes

Reload the user groups every time the volume configuration changes
and also to call initgroups() again with the possibly changed groups.

FR #71
Merge remote-tracking branch 'origin/develop' into spotlight

Conflicts:
	config/Makefile.am
	etc/afpd/afp_dsi.c
	etc/afpd/auth.c
	include/atalk/Makefile.am
Add support for searches for folders