Feature/windows installer

Here is a pretty basic yet usefull installer for the windows platform. It uses launch4j to generate a .exe wrapper and packages all the required files in a NSIS installer program. The generated installer is smart enough to detect winpcap availability and installs it if necessary. see README for the build instructions.

As a reminder, here are the licenses of both tools.

- Launch4j : This program is free software licensed under the BSD license, the head subproject (the code which is attached to the wrapped jars) is licensed under the MIT license. Launch4j may be used for wrapping closed source, commercial applications.

- NSIS : NSIS (Nullsoft Scriptable Install System) is a tool that allows programmers to create such installers for Windows. It is released under an open source license and is completely free for any use.(http://nsis.sourceforge.net/Docs/AppendixI.html#I)