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.

nselib/bits.lua

@@ -0,0 +1,66 @@
+---
+-- Bit manipulation library.
+--
+-- @author Patrick Donnelly <batrick@batbytes.com>
+-- @copyright Same as Nmap -- see https://nmap.org/book/man-legal.html
+-- @see https://www.lua.org/manual/5.3/manual.html#3.4.2
+
+local assert = assert
+local error = error
+
+local _ENV = {}
+
+--- Reverses bits in integer.
+--
+-- @param n The integer.
+-- @param size The bit width of the integer (default: 8).
+-- @return The reversed integer.
+function reverse (n, size)
+    if not size or size == 8 then
+        n = n & 0xff
+        n = (n & 0xf0) >> 4 | (n & 0x0f) << 4
+        n = (n & 0xcc) >> 2 | (n & 0x33) << 2
+        n = (n & 0xaa) >> 1 | (n & 0x55) << 1
+        n = n & 0xff
+    elseif size == 32 then
+        n = n & 0xffffffff
+        n = ((n >> 1) & 0x55555555) | ((n & 0x55555555) << 1);
+        n = ((n >> 2) & 0x33333333) | ((n & 0x33333333) << 2);
+        n = ((n >> 4) & 0x0F0F0F0F) | ((n & 0x0F0F0F0F) << 4);
+        n = ((n >> 8) & 0x00FF00FF) | ((n & 0x00FF00FF) << 8);
+        n = ( n >> 16             ) | ( n               << 16);
+        n = n & 0xffffffff
+    else
+        error("invalid size: "..size)
+    end
+    return n
+end
+
+do
+    local function test8 (a, b)
+        local r = reverse(a, 8)
+        if r ~= b then
+            error(("0x%02X: expected 0x%02X, got 0x%02X"):format(a, b, r))
+        end
+    end
+    test8(0x00, 0x00)
+    test8(0x01, 0x80)
+    test8(0x80, 0x01)
+    test8(0xff, 0xff)
+    test8(0x88, 0x11)
+    test8(0x5c, 0x3a)
+
+    local function test32 (a, b)
+        local r = reverse(a, 32)
+        if r ~= b then
+            error(("0x%08X: expected 0x%08X, got 0x%08X"):format(a, b, r))
+        end
+    end
+    test32(0x00000000, 0x00000000)
+    test32(0x00000001, 0x80000000)
+    test32(0x80000000, 0x00000001)
+    test32(0xffffffff, 0xffffffff)
+    test32(0x22221234, 0x2c484444)
+end
+
+return _ENV