Adds support for Lua Int64 and UInt64 operators, functions, and general

Adds support for Lua Int64 and UInt64 operators, functions, and general
usefulness, working around bug #9162 until Lua 5.3 is released.

The existing Int64 and UInt64 classes provide virtually no
usefullness, other than for creating a string of their value.  While
one could then write Lua code to convert the string to Lua numbers and
such, ultimately Lua has no native 64-bit integer support, making such
a task difficult to handle in Lua.  This change adds a host of
functions and operators to the existing Int64 (gint64) and UInt64
(guint64) classes, to enable true 64-bit integer support on par with
native Lua numbers.

A test script is also provided, which tests the functions/operators.

Change-Id: I4c5f8f5219b9a88198902283bd32ddf24c346bbe
Reviewed-on: https://code.wireshark.org/review/83
Tested-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Evan Huus <eapache@gmail.com>