Fixed bug when line in todo dropdown starts with `vim:`, `vi:`, or `:ex`
which would automatically be read by vim and tried to be set in the
editor. Removed modeline reading from vim to fix the bug, and since it
provides quite an attack vector anyway.
Added Limelight to its startup procedure to highlight the current to-do
paragraph.
Dropdown services need an X server to connect to and fail autostarting
if there's no available server.
HACK
Increasing their restart timer will alleviate this problem, *but* it
also means the dropdowns will start more slowly when closed by the user.
There should be another way to alleviate one issue (start automatically
after X is available) without exacerbating the other (restart when you
have been closed).
