Disable more useless GNOME session processes on Jessie
E.g. we're currently running
/usr/lib/telepathy/mission-control-5. Probably not all of those are useful in Tails. Getting rid of some of them would help avoid Tails/Jessie require too much RAM.
Disable a few unneeded D-Bus services.
Some of these services are automatically started (via D-Bus activation) when
GNOME Shell tries to use them. The only "use" I've seen for them, except sucking
precious RAM, is to display "No appointment today" in the calendar pop-up.