This first bit of code aims to add a "map" to the packet functionality
that is able to translate to and from "method strings" to "command ids".
IDs are sent across the wire, and they're now integers. This removes the
need for the strings to be present in things like native meterp, and
hence makes things a little less obvious on the wire, and way less
obvious on disk/in the payload.
Given that we need this functionality in other Meterpreters to support
the removal of strings, some code has been added that can generate
source files for Python, C# and C. This code might move, but for now
it's at least in a spot where it's used the most.
OJ