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.

nse_utility.h

@@ -43,6 +43,14 @@ void nseU_setsfield (lua_State *L, int idx, const char *field, const char *value
  */
 void nseU_setnfield (lua_State *L, int idx, const char *field, lua_Number value);
 
+/* void nseU_setifield (lua_State *L, int idx,             [-0, +0, e]
+ *                      const char *field, lua_Integer value)
+ *
+ * Sets the field for table at index idx to numerical value.
+ *  (t[field] = value).
+ */
+void nseU_setifield (lua_State *L, int idx, const char *field, lua_Integer value);
+
 /* void nseU_setbfield (lua_State *L, int idx,             [-0, +0, e]
  *                      const char *field, int value)
  *