Debian packaging for Gradle 2.x

HOW TO USE:

gem install fpm
./gradle-mkdeb.sh

The script will download a Gradle binary distribution from gradle.org, unpack it, and use fpm to produce a .deb package.

The deb will put Gradle at /opt/gradle-${VERSION}/bin/gradle, and will use update-alternatives to install a symlink on the system at /usr/bin/gradle.