Change package name due to ABI breaking changes and drop policy file

This is in accordancee with section 3.2.1 "Naming & Versioning" of the
Debian CLI policy.
Use the snk file from upstream for assembly signing

Since the this update already breaks the ABI, we can switch to the
new signing keys from upstream.
uuencode gpg key file from upstream
Add debian/GeneratedAssemblyInfo.cs

This file has been generated the svn checkout
http://svn.apache.org/viewvc/logging/log4net/tags/1.2.13/
with "nant -t:mono-2.0".
Update build command based on the upstream nant build
Update Vcs fields to point to anonscm.debian.org
Fix some Lintian warnings

 * debian/control:
     - ancient-standards-version
     - wrong-section-according-to-package-name

 * debian/rules: debian-rules-missing-recommended-target
Make debian/copyright file machine-readable

This fixes Lintian errors
 * copyright-file-contains-full-apache-2-license
 * copyright-should-refer-to-common-license-file-for-apache-2

Copyright statement for debian diretory has been inferred
from debain/changelog and git commits.
Finalize changelog