This script should be in the root of the git repo so that the config in
Jenkins' web interface is always just:
./jenkins-build
This commit also includes a little code to make it easier for people to run
this script on their own machines, if they want to reproduce the Jenkins
build setup.
Jenkins will then call ant directly after running this script. This then sets
the debug builds made by Jenkins to have a versionCode of the UNIX time in
seconds and adds the data to the versionName. This clearly marks these as
debug builds and also makes it possible to have an fdroid repo of debug builds
that will automatically update after each build.
