Add a new msrpc.lua module, plus new scripts smb-enumdomains.nse,

smb-enumshares.nse, and smb-enumusers.nse. Also enhance the netbios.lua and
smb.lua modules. Remove the smb-enum.nse script. All these changes are from Ron
Bowes.

scripts/smb-security-mode.nse

@@ -1,25 +1,25 @@
---- Returns information about the SMB security level determined by SMB. 
---
--- Here is how to interpret the output:
---
+--- Returns information about the SMB security level determined by SMB. \n
+--\n
+-- Here is how to interpret the output:\n
+--\n
 -- User-level security: Each user has a separate username/password that is used
 --  to log into the system. This is the default setup of pretty much everything
---  these days. 
+--  these days. \n
 -- Share-level security: The anonymous account should be used to log in, then 
 --  the password is given (in plaintext) when a share is accessed. All users who
 --  have access to the share use this password. This was the original way of doing
 --  things, but isn't commonly seen, now. If a server uses share-level security, 
---  it is vulnerable to sniffing. 
---
+--  it is vulnerable to sniffing. \n
+--\n
 -- Challenge/response passwords: If enabled, the server can accept any type of
---  password:
---  * Plaintext
---  * LM and NTLM
---  * LMv2 and NTLMv2
+--  password:\n
+--  * Plaintext\n
+--  * LM and NTLM\n
+--  * LMv2 and NTLMv2\n
 -- If it isn't set, the server can only accept plaintext passwords. Most servers
 --  are configured to use challenge/response these days. If a server is configured
---  to accept plaintext passwords, it is vulnerable to sniffing. 
---
+--  to accept plaintext passwords, it is vulnerable to sniffing. \n
+--\n
 -- Message signing: If required, all messages between the client and server must
 --  sign be signed by a shared key, derived from the password and the server 
 --  challenge. If supported and not required, message signing is negotiated between
@@ -27,18 +27,18 @@
 --  don't sign messages, so if message signing isn't required by the server, messages
 --  probably won't be signed; additionally, if performing a man-in-the-middle attack,
 --  an attacker can negotiate no message signing. If message signing isn't required, the 
---  server is vulnerable to man-in-the-middle attacks. 
--- 
---  See nselib/smb.lua for more information on the protocol itself. 
---
+--  server is vulnerable to man-in-the-middle attacks. \n
+-- \n
+--  See nselib/smb.lua for more information on the protocol itself. \n
+--\n
 --@usage
 -- nmap --script smb-security-mode.nse -p445 127.0.0.1\n
 -- sudo nmap -sU -sS --script smb-security-mode.nse -p U:137,T:139 127.0.0.1\n
 --
 --@output
--- |  SMB Security: User-level authentication
--- |  SMB Security: Challenge/response passwords supported
--- |_ SMB Security: Message signing supported
+-- |  SMB Security: User-level authentication\n
+-- |  SMB Security: Challenge/response passwords supported\n
+-- |_ SMB Security: Message signing supported\n
 -- 
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