Update dependencies
Add gnome-base/libgnome-keyring to dependencies
Add x11-libs/gtk+:2, x11-libs/libnotify dependencies
Add libchromiumcontent.so dependencies

- dev-libs/nss
- dev-libs/nspr
- gnome-base/gconf
- media-libs/alsa-lib
- net-print/cups
Merge pull request #14 from aegypius/14-atom-shell-ebuild-fails-to-install

atom-shell ebuild fails to install