Merge branch 'nse-lua53'

Lua 5.3 adds several awesome features of particular interest to nmap including
bitwise operators and integers, a utf8 library, and standard binary pack/unpack
functions.

In addition to adding Lua 5.3, this branch changes:

o Complete removal of the NSE bit library (in C), It has been replaced with
  a new Lua library wrapping Lua 5.3's bit-wise operators.

o Complete removal of the NSE bin library (in C). It has been replaced with a
  new Lua library wrapping Lua 5.3's string.pack|unpack functions.

o The bin.pack "B" format specifier (which has never worked correctly) is
  unimplemented.  All scripts/libraries which use it have been updated. Most
  usage of this option was to allow string based bit-wise operations which are no
  longer necessary now that Lua 5.3 provides integers and bit-wise operators.

o The base32/base64 libraries have been reimplemented using Lua 5.3's new
  bitwise operators. (This library was the main user of the bin.pack "B" format
  specifier.)

o A new "bits" library has been added for common bit hacks. Currently only has
  a reverse function.

Thanks to David Fifield, Daniel Miller, Jacek Wielemborek, and  Paulino
Calderon for testing this branch.

scripts/http-vuln-cve2014-3704.nse

@@ -1,6 +1,5 @@
 local bit = require "bit"
 local http = require "http"
-local math = require "math"
 local shortport = require "shortport"
 local stdnse = require "stdnse"
 local string = require "string"
@@ -162,7 +161,7 @@ end
 local function gen_passwd_hash(passwd)
   local iter = 15
   local iter_char = itoa64(iter)
-  local iter_count = math.pow(2, iter)
+  local iter_count = 1<<iter
   local salt = stdnse.generate_random_string(8)
 
   local md5 = openssl.md5(salt .. passwd)