virtualbox+guest: Update to new upstream v4.2.12.

All patch files dropped because they're fixed in this release. For a full list
of fixes that come with this maintenance release, please refer to:

https://www.virtualbox.org/wiki/Changelog

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
chromium: Update all channels to latest versions.

stable:   26.0.1410.43              -> 26.0.1410.63 (builds fine, tested)
beta/dev: 27.0.1453.15/27.0.1453.12 -> 27.0.1453.47 (builds fine, tested)

This should bring beta and dev in par, as dev was older than the beta version.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>