show upgradable packages after apt update

Closes: 748389
Show unauthenticated warning for source packages as well

This will show the same unauthenticated warning for source packages
as for binary packages and will not download a source package if
it is unauthenticated. This can be overridden with
--allow-unauthenticated

Closes: #749795
Add compat mode for old (32bit FileSize) CacheDB (LP: #1274466)
add pkgSrcRecords::Next() to step through all the pkgSrcRecords
Merge remote-tracking branch 'mvo/feature/srcrec-enum2' into debian/sid
Merge remote-tracking branch 'mvo/bugfix/lp1274466-cache' into debian/sid
Merge remote-tracking branch 'mvo/bugfix/apt-get-source-unauthenticated-warning' into debian/sid
Merge remote-tracking branch 'mvo/feature/apt-update-info' into debian/sid
prepare 1.0.4 upload
use pkgSrcRecords::Step() instead of Next()
fix test/integration/test-apt-ftparchive-cachedb-lp1274466 in travis
apt-private/private-output.cc: fix cppcheck output
release 1.0.4
really release 1.0.4
fix autopkgtest tests
fix test-apt-ftparchive-cachedb-lp1274466 and apt-internal-solver tests
test/integration/test-essential-force-loopbreak: fix on non-amd64 systems
Check for gtest's header before building.

Add AC_CHECK_HEADER directive for gtest, and report a fatal error message if not
found.
Updated translation of german documentation
Merge remote-tracking branch 'mvo/debian/sid' into debian/sid