Reduce overhead, don't duplicate the string.

Reduce overhead.

Move global variables into the new classes.  That may allow multiple
update threads for multiple databases one day.

Allows the kernel to combine timer wakeups with other processes,
reducing power usage.

Don't use global variables.

Decouple command/OtherCommands.cxx from the "simple" database plugin.

Don't depend on the "simple" database plugin.  This fixes an assertion
failure / crash and allows using stickers with other plugins.

Make it "const".

sed gone horribly wrong.  D'oh!

pthread_setname_np() doesn't have the "thread" argument on OS X.

Fixes non-Linux build without neighbor plugins.

Another big chunk of code for multi-player support.

The pkg-config file has been added in Samba 4.0.  This commits adds a
fallback for older libsmbclient versions.