Replace "buffered socket" classes with socket.receive_buf()

The match library has a helpful function for doing exactly this, with
less copy-and-pasted code:
http://nmap.org/nsedoc/lib/match.html#numbytes

nselib/ncp.lua

@@ -25,9 +25,6 @@
 --    - Contains the "native" NCP functions sending the actual request to the
 --      server.
 --
--- * Socket
---    - A buffered socket implementation
---
 -- * Helper
 --    - The prefered script interface to the library containing functions
 --      that wrap functions from the NCP class using more descriptive names
@@ -56,6 +53,7 @@
 local bin = require "bin"
 local bit = require "bit"
 local ipOps = require "ipOps"
+local match = require "match"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
 local string = require "string"
@@ -622,7 +620,7 @@ Response = {
   -- @param socket socket connected to server and ready to receive data
   -- @return Response containing a new Response instance
   fromSocket = function(socket)
-    local status, header = socket:recv(16)
+    local status, header = socket:receive_buf(match.numbytes(16), true)
     if ( not(status) ) then return false, "Failed to receive data" end
 
     local pos, sig, len = bin.unpack(">II", header)
@@ -631,7 +629,7 @@ Response = {
     local data
 
     if ( 0 < len - 16 ) then
-      status, data = socket:recv(len - 16)
+      status, data = socket:receive_buf(match.numbytes(len - 16), true)
       if ( not(status) ) then return false, "Failed to receive data" end
     end
     return true, Response:new(header, data)
@@ -977,7 +975,8 @@ Helper = {
   --- Connect the socket and creates a NCP connection
   -- @return true on success false on failure
   connect = function(self)
-    self.socket = Socket:new()
+    self.socket = nmap.new_socket()
+    self.socket:set_timeout(5000)
     local status, err = self.socket:connect(self.host, self.port)
     if ( not(status) ) then return status, err end
 
@@ -1077,76 +1076,6 @@ Helper = {
   end,
 }
 
-Socket =
-{
-  new = function(self)
-    local o = {}
-    setmetatable(o, self)
-    self.__index = self
-    o.Socket = nmap.new_socket()
-    o.Buffer = nil
-    return o
-  end,
-
-  --- Sets the socket timeout (@see nmap.set_timeout)
-  -- @param tm number containing the socket timeout in ms
-  set_timeout = function(self, tm) self.Socket:set_timeout(tm) end,
-
-  --- Establishes a connection.
-  --
-  -- @param hostid Hostname or IP address.
-  -- @param port Port number.
-  -- @param protocol <code>"tcp"</code>, <code>"udp"</code>, or
-  -- @return Status (true or false).
-  -- @return Error code (if status is false).
-  connect = function( self, hostid, port, protocol )
-    self.Socket:set_timeout(5000)
-    return self.Socket:connect( hostid, port, protocol )
-  end,
-
-  --- Closes an open connection.
-  --
-  -- @return Status (true or false).
-  -- @return Error code (if status is false).
-  close = function( self )
-    return self.Socket:close()
-  end,
-
-  --- Opposed to the <code>socket:receive_bytes</code> function, that returns
-  -- at least x bytes, this function returns the amount of bytes requested.
-  --
-  -- @param count of bytes to read
-  -- @return true on success, false on failure
-  -- @return data containing bytes read from the socket
-  --         err containing error message if status is false
-  recv = function( self, count )
-    local status, data
-
-    self.Buffer = self.Buffer or ""
-
-    if ( #self.Buffer < count ) then
-      status, data = self.Socket:receive_bytes( count - #self.Buffer )
-      if ( not(status) or #data < count - #self.Buffer ) then
-        return false, data
-      end
-      self.Buffer = self.Buffer .. data
-    end
-
-    data = self.Buffer:sub( 1, count )
-    self.Buffer = self.Buffer:sub( count + 1)
-
-    return true, data
-  end,
-
-  --- Sends data over the socket
-  --
-  -- @return Status (true or false).
-  -- @return Error code (if status is false).
-  send = function( self, data )
-    return self.Socket:send( data )
-  end,
-}
-
 --- "static" Utility class containing mostly conversion functions
 Util =
 {