Builder: Added autobuild command to package the source tarball

The tarball is then copied to the build directory.

Next: Publish .tar.gz files.
Builder: Cleanup
Merge branch 'master' of ssh://git.code.sf.net/p/deng/code into builder-src-package
Builder|Debian|Ubuntu: Create a source package and upload it to Launchpad

After putting together a tarball, also create a Debian source package
and upload it to a Launchpad PPA (ppa:sjke/doomsday).
Fixed|Builder|Debian|Ubuntu: Version number of source package

The Debian convention is that a version number suffix is used for the
Debian-specific version number and it is not part of the actual/original
version number. Therefore it is not appropriate to use the "-buildxxx"
suffix.

The build number is now appended as the fourth version number component,
i.e., 1.13.0.1042.
Builder|Debian|Ubuntu: Set a fixed build number in the build rules

By default the rules are set to build for today's number, but a packaged
source should use a fixed build number.
Builder|Pilot: After binary build, package the source

The source package will be included in the signed files and will then
be published to SourceForge. The source package will also be pushed to
the sjke/doomsday PPA.