The formatter library wasn't advertised in any .pc file, which could
break 3rd-party plugins like evolution-rss with missing symbols from
the formatter.
These libraries are bound for E-D-S so they live at the lowest layer of
Evolution for now -- even libeutil can link to them (but please don't).
This is the first step toward moving mail handing to a D-Bus service.
evolution-mail-3.0 and evolution-calendar-3.0 should require
evolution-shell-3.0. evolution-mail and evolution-calendar should
require evolution-shell.
