run autopkgtest against the installed apt
make apt-key net-update actually testable
fix apt-key net-update test to use the buildin webserver
make /etc/apt/preferences parser deal with comment only sections
factor GetTempDir out
add basic tests for GetTempDir()
add integration test
Merge branch 'feature/policy-parser-bts732746' into debian/sid
Merge branch 'feature/test-apt-key-net-update' into debian/sid
Merge branch 'feature/tests-on-installed' into debian/sid