This is the registry library. The registry is basically a bunch of
hives, each of which is loaded from a file. When using a local registry, 
it is possible to specify where hives should be loaded from, etc. 

There are separate APIs for accessing the data in a hive and the 
data in the registry itself. Each supports different backends. 

The following "full registry" backends are currently provided:

 * Remote (over DCE/RPC)
 * Local (allows "mounting" hives)
 * Wine (uses the wine plain-text file)

The following hive backends are supported:

 - ldb 
 - regf (NTUSER.DAT-style files)
 - rpc (Remote individual hives)
 - directory

reg_open_samba() loads a set of hives based on smb.conf settings.
Lines in smb.conf should have the following syntax:

registry:<hivename> = <backend>:<location>

So an example usage could be:

registry:HKEY_CURRENT_USER = regf:NTUSER.DAT
registry:HKEY_LOCAL_MACHINE = ldb:tdb://registry.tdb

WERR_NOT_SUPPORTED will be returned for all hives that haven't been set.

On Windows the various registry hives are loaded from:

HKEY_CURRENT_CONFIG: %SystemRoot%\System32\Config\System
HKEY_CURRENT_USER: %Profile%\NTUser.dat
HKEY_LOCAL_MACHINE\SAM: %SystemRoot%\System32\Config\Sam
HKEY_LOCAL_MACHINE\Security: %SystemRoot%\System32\Config\Security
HKEY_LOCAL_MACHINE\Software: %SystemRoot%\System32\Config\Software
HKEY_LOCAL_MACHINE\System: %SystemRoot%\System32\Config\System
HKEY_USERS\.DEFAULT: %SystemRoot%\System32\Config\Default
HKEY_LOCAL_MACHINE\HARDWARE: is autogenerated
