coredump: bump coredump truncation size from 24M to 768M

In the long run we really should make this runtime configurable.
inhibit: make the output more readable

The columnar output can become pretty horrible. When GNOME inhibits
power/suspend/hibernate keys, the "WHAT" column's text extends to "WHO"
and even "WHY". At the same time, all texts in "WHY" are of the form

    GNOME handlin...sses
    Receiving sle...ions
    GNOME needs t...reen

This patch splits each inhibit entry into four lines, allowing the full
text to fit in a normal-width terminal.
update TODO