Added niflib as submodule, and added script for creating source archive.

.gitmodules

+[submodule "niflib"]
+	path = niflib
+	url = git://niftools.git.sourceforge.net/gitroot/niftools/niflib

makezip.sh

+#!/bin/bash
+
+# quick script to create zip file containing all sources
+# uses https://github.com/amorilia/git-archive-all
+git clean -xfd
+git-archive-all max_nif_plugin-`git log -1 --pretty=format:%h`.zip --prefix max_nif_plugin/ -v

niflib @ dd61b979

+Subproject commit dd61b9790f53a6abfd0f871e1bc6a87082b47cda