Updated ubuntu builder project configuration files. Added pinned packages to unattended upgrades. Removed connected dektop file (integrated now into linkedin system). Added desktop file for system menu editor. Removed gistbox desktop file (added now as chromium extension). Removed popcorn desktop file (not compatible with chromium). Removed twitter desktop file, replaced by the much more capable tweetdeck chromium extension. Added various ubuntu branding images to revert from new ubuntude-branding project.