Merged in my changes from nmap-smb. The primary changes are:

* Updated the way authentication works on smb -- it's significantly cleaner now
* smb-enum-shares.nse gives significantly better output now (it checks if shares are writable)
* Added a script that checks if smbv2 is enabled on a server
* Added smb-psexec, a script for executing commands on a remote Windows server. I also included some default scripts, a compiled .exe to run everything, and a ton of documentation (in the form of NSEDoc)
* Added 'override' parameters to some of the functions in smb.lua, which lets the programmer override any field in an outgoing SMB packet without modifying smb.lua. 
* Lots of random code cleanups in the smb-* scripts/libraries

nselib/data/psexec/pwdump.lua

@@ -0,0 +1,53 @@
+module(... or "pwdump", package.seeall)
+---This config file is designed for running password-dumping scripts. So far, 
+-- it supports pwdump6 2.0.0 and fgdump.
+--
+-- Note that none of these modules are included with Nmap by default. 
+
+-- Any variable in the 'config' table in smb-psexec.nse can be overriden in the
+-- 'overrides' table. Most of them are not really recommended, such as the host,
+-- key, etc.
+overrides = {}
+--overrides.timeout = 40
+
+modules = {}
+local mod
+
+--mod = {}
+--mod.upload           = true
+--mod.name             = "PwDump6 2.0.0"
+--mod.program          = "PwDump.exe"
+--mod.args             = "localhost"
+--mod.maxtime          = 10
+--mod.include_stderr   = false
+--mod.url              = "http://www.foofus.net/fizzgig/pwdump/"
+--table.insert(modules, mod)
+
+---Uncomment if you'd like to use PwDump6 1.7.2 (considered obsolete, but still works). 
+-- Note that for some reason, this and 'fgdump' don't get along (fgdump only produces a blank
+-- file if these are run together)
+--mod = {}
+--mod.upload           = true
+--mod.name             = "PwDump6 1.7.2"
+--mod.program          = "PwDump-1.7.2.exe"
+--mod.args             = "localhost"
+--mod.maxtime          = 10
+--mod.include_stderr   = false
+--mod.extrafiles       = {"servpw.exe", "lsremora.dll"}
+--mod.url              = "http://www.foofus.net/fizzgig/pwdump/"
+--table.insert(modules, mod)
+
+-- Warning: the danger of using fgdump is that it always write the output to the harddrive unencrypted; 
+-- this makes it more obvious that an attack has occurred. 
+mod = {}
+mod.upload           = true
+mod.name             = "FgDump"
+mod.program          = "fgdump.exe"
+mod.args             = "-c -l fgdump.log"
+mod.maxtime          = 10
+mod.url              = "http://www.foofus.net/fizzgig/fgdump/"
+mod.tempfiles        = {"fgdump.log"}
+mod.outfile          = "127.0.0.1.pwdump"
+table.insert(modules, mod)
+
+