Create .deb binary packages with ant. See Issue #114

I have updated the build.xml file to create a .deb binary package in addition to the tarball distribution.  Invoking ant dist on a linux system will now create a .deb file and a .tgz file.  Creating a .deb file requires the fakeroot program which can be installed through your favorite package manager on most systems.  You may even already have it installed.  You will also need dpkg-deb which should already be installed.  Like the .tgz file you will need to build it using a system with same architecture as the desired package (32-bit or 64-bit).  

The .deb package adds the following benefits as opposed to the .tgz.  You can install (reinstall and update as well) the package using dpkg, gdebi, ubuntu software center, or other .deb compatible package managers (I have tested the three listed here).  There is no ppa setup so you cannot do apt-get install.  The files are installed into the /opt directory and a symlink is created in the /usr/bin directory so you can launch processing from a terminal.  A processing.desktop file and a mime-type file are added so that you can launch processing from the GUI and associate .pde files with processing.  By default the .pde files are not associated with processing.  

If you have previously created your own processing.desktop or mime-type files for processing you may want to remove these before installing the .deb package to avoid conflicts and/or confusion.  

Although the .deb package does not conform to all debian package requirements, a reasonable attempt was made at conformance and the package should install without producing any errors.  I included a basic attempt at documenting the known copyrights and licenses used.  No change log is currently included.