Remove code to handle bug closures differently for NMUs or experimental uploads and just let version tracking sort it out instead.

[rmurray] change default compression scheme for both Sources and Packages to gzip and bzip2 rather than uncompressed and gzip (Packages) and gzip (Sources).  Use old defaults for proposed-updates.

[rmurray] BTS pseudo packages: drop install, installation, boot-floppy, slink-cd, potato-cd and nonus.debian.org.  Update base.

ensure the Source: field in changes files is a package name.  Support new dpkg optional version in the field, too.

fix, and stats fix.